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Look Inside. Predicting Stock Prices by Analysing an Enterprise |
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Intranet Social Network and Using Word Co -Occurrence |
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Networks |
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Fronzetti Colladon, A., & Scettri, G. |
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This is the accepted manuscript after the review process, but prior to final layout |
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and copyediting . Please cit e as: |
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Fronzetti Colladon, A., & Scettri, G. (2019). Look Inside. Predicting Stock |
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Prices by Analysing an Enterprise Intranet Social Network and Using Word Co - |
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Occurrence Networks. International Journa l of Entrepreneurship and Small |
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Business, 36(4), 378 -391. https://dx.doi .org/10.1504/IJESB.2019.098986 |
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This work is licensed under the Creative Commons Attribution - |
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letter to Creative Commons, PO Box 1866, Mountain View, CA 94042, USA. 1 |
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Look Inside. Predicting Stock Prices by Analysing an |
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Enterprise Intranet Social Network and Using Word Co - |
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Occurrence Networks |
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Fronzetti Colladon , A., & Scettri, G. |
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Abstract |
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This study looks into the employees’ communication behaviours taking place in an intranet social |
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network , offering novel metrics of Semantic and Social Network Analysis, which can help predict a |
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company stock price. To this purpose, w e studied the intranet forum of a large Italian company, |
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exploring the interaction s and the use of language of about 8,000 employees . We analyse d more |
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than 48,000 news and comments , over a period of 94 weeks . In addition to using more traditional |
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semantic and social network metrics, we built a network linking words included in the general |
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discourse. In this network, we focused on the posit ion of the node representing the company brand. |
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We f ound that a lower se ntiment of the language used , a higher betwe enness centrality of the |
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company brand, a denser word co -occurrence network and more equally distributed centrality |
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scores of employees (lower group betweenness centrality) are all significant predictors of higher |
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stock prices. Our findings contribute to the strea m of research concerned with the prediction of |
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stock prices , offering new metrics that can be helpful for scholars , company man agers and |
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professional investors and could be integrated in to existing forecasting models to improve their |
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accuracy . We also show the importance of looking at internal communication streams while |
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analysing a company’s financial performance . Lastly , we contribute to the research on word co - |
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occurrence network s by extend ing their field of application. |
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2 |
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Keywords: stock price; economic forecasting; intranet; social network; web forum; semantic |
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analysis; word co -occurrence network . |
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1. Introduction |
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The question whether stock market prices are predictable is frequent in literature, especially after |
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financial crisis (Cowles, 1933; Bollerslev and Ole Mikkelsen, 1996; Barro, 2015) . In recent years , |
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new approaches were presented, comprising the analysis of co mplex system s and data mining and |
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machine learning techniques (Kuo, Chen and Hwang, 2001; Sornette, 2003) . With the complex |
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system approach it is poss ible to model the influence of the various agent s that operate in a market |
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(investors, companies , bank s, nations , etc.. ), investigating their reciprocal interactions (Grimm, |
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2005) . Data mining offers the possibility to analyse large volumes of data , retrieved from different |
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sources , such as stock indices , social media or other online platforms . Nowadays researchers can |
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take advantage of datasets never seen before, in which interesting information can be hidden. |
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In this paper, we combine methods and tools from Social Network and Semantic Analysis |
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(Wasserman and Faust, 1994; Aggarwal and Zhai, 2013) , while investigating the interactions taking |
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place in the intranet forum of a large Italian company. We study the interaction patterns of the |
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company employees with regard to their activity levels, network positions an d use of language , |
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while posting news and comments . Additionally, we pro pose a novel method to transform the |
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general discourse into a network of words (Danowski, 2009) , thus analys ing the positions and |
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fluctuations of the company brand in that network. Our scope is to understand if there are hidden |
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associations between th ese patterns and the company stock price at specific time lags . In this |
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regard, we offer a novel contribut ion since we use a new information source – which, to the extent |
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of our knowledge, has never been used for the same exact purpose – and study original metrics |
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obtained from the combination of semantic and social network analysis . In other words, the |
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objective of this paper is to extract new variables fr om the analysis of the communication taking 3 |
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place in a large intranet social network , show ing the value of these new predictors for the |
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forecasting of stock prices : we investigate if it is possible to look at employees’ communication |
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behaviours to better predict the firm market value . This research also offers an additional |
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contribut ion to increase the knowledge about possible use s of word co -occurrence network s. |
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2. Network and Semantic Analysis for Stock Market Predictions |
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The use of network theory to analyse stock market trend s evolved around two main approaches: |
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empirical and theoretical. T he first is centred on the experimental way s by which network s are |
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created, as in the work of Sun et al. (2015) , who connect ed stock prices with other market attributes |
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(e.g., trading volume s or net return s). The t heoretical approach , on the other hand, is focused on the |
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evaluation of the problem in a general form : given some mathematical conditions related to the |
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network, the aim is to demonstra te the existence and uniqueness of a solution (Barucca et al. , 2016) . |
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Studies applying network theor ies were successfully implemented to analyse the behaviour of |
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Brazilian (Tabak et al. , 2009) , Chinese (Huang, Zhuang and Yao, 2009) and Indian (Pan and Sinha, |
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2007) stock marke ts. Tabak et al. (2009) tried to figure out if the Brazilian stock price returns |
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present ed a power law distribution . Their result s show ed that, for most of the study period , a power |
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law distribution is not representative of the phenomenon. This suggests that the dynamics of stock |
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prices may change abruptly , being more complicated than a power law distribution, especially when |
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critical events occur . Huang and colleagues (2009) used a threshold method to build a social |
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network considering the correlations among 1080 stocks in the Chinese market and their daily |
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prices for about four years. Testing the topological stability of the network, they found it to be |
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robust against random vertex failures, but fragile against targeted attack s; in this way they offered |
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insights for risk and portfolio management . Similarly, Pan and Sinha (2007) analysed the cross - |
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correlation matrix of stock price s fluctuations in the Indian National Stock Exchange. This market |
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exhibit ed strong er correlations when compared to more mature markets , such as the New York 4 |
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Stock Exchange . Pan and Sinha (2007) showed that the existence of an internal structure made of |
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multiple connected groups is a possible indicator of market development. |
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Other authors addressed the problem of interdependence between stock markets (Morana and |
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Beltratti, 2008; Sedik and Williams, 2011) , suggesting the inclusion of control indices while |
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making stock price predictions. In particular, Sedik and Williams (2011) used a GARCH model to |
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study the influence of the volatility of U.S. and regional equity markets on the conditional volatility |
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of stock prices in the Gulf Cooperation Council’s m arket. Morana and Beltratti (2008) , showed a |
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link among the variance s of the stock market indices of US, UK, Japan and Germany . |
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Recently , the improvement of sentiment analysis and other social media related research , offered |
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new possibilities, combining stock market predictions with metrics extracted from online platforms , |
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such as Twitter or Facebook (Zhang, Fuehres and Gloor, 2011; Chen and Lazer, 2013; Makrehchi, |
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Shah and Liao, 2013) . Measuring the sentiment of the conversations about a specific company, |
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scholars proved the influence of positive and negative feelings on stock market prices (Chung and |
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Liu, 2011; Elshendy et al. , 2017) . To this purpose, Khadjeh et al. (2014) and Schumaker and Chen |
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(2009) used sentiment analysis combined with linear regression models and support vector |
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machines . In the former study, authors used the text of breaking financial new s-headlines to |
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forecast currency movements in the foreign exchange market . In the latter study, autho rs succeeded |
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in partially predict ing future stock price s twenty minutes after a financial article was released : they |
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used several different textual representations – such as Bag of Words, Noun Phrases (Caropreso and |
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Matwin, 2006) and Named Entities (Diesner and Carley, 2005 ). Zhang et al. (2011) analysed |
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Twitter with a similar purpose, tagging tweets according to feelings of fear, general concern and |
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hope ; they found a negative correlation between the sentiment trend of the tagging variables and the |
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Dow Jones, NASDAQ and S&P 500 . Antweiler and Frank (2004) studied the influence of messages |
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in Yahoo!Finance over a set of 45 stock market prices of private companies . Similarly, Xie et al. |
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(2013) crawled Yahoo!Finance and developed a tree representation for word s in sentences, which |
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performed significantly better than approaches based on bag-of-words in predicting the polarity of 5 |
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stock price s trends . A different approach for the sentiment analysis of tweets is to use non- |
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parametric topic mode lling algorithms , as proposed by Si et al. (2013) . |
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In the paper of Bollen Mao and Zeng (2011) the prediction of the Dow Jones Industrial Average |
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was done by analysing the text content of daily Twitter feeds by means of two mood -tracking tools : |
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OpinionFinder – which tracks positive and negative mood s – and Google Profile of Mood States |
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(GPOMS) , which measure s language mood in term of six dimensions (Calm, Alert, Sure, Vital, |
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Kind, and Happy) . Rechenthin et al. (2013) tried to understand if there were financial agents that |
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could manipulate sentiment trend s, to influence stock market price s posting specific, either positive |
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or negative, messages on specialized financial website s. Nguyen et al. (2014) analyzed the main |
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topics and sentiment of eighteen Yahoo!Finance message boards for eighteen stocks . On message |
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boards, users discussed company news, fa cts or comments (often negative) about specific company |
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events, and personal forecasts. Analysing such platforms can be helpful, also because users have the |
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possibility to annotate message with tags (e.g., Strong Buy, Buy, Hold, Sell and Strong Sell). |
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Auth ors proved that adding sentiment analysis to models based on historical prices trends can |
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increase the predictive power of such models. |
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Yang et al. (2015) demonstrated the existence of Twitter ’s financial communities – which presented |
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a small -world structure – inferred studying friend -following relationship s and user profile s, |
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including language preference s, location s, account creation date s and time zone s. Looking at the |
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sentiment of the tweets sent by people in the most central network positions, the authors could |
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predict financial market indices. |
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Lastly, other techniques were also implemented with the aim of improving stock prices prediction s, |
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such as a rtificial neural network s. Patel and Yalamalle (2014) , for example, achieved good results |
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using neural networks to predict stock price s in India. |
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Semantic and social network analysis of the communication of employees proved their value for |
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several purposes, such as predicting turnover intentions (Gloor et al., 2017 a), improving customer 6 |
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satisfaction (Gloor and Giacomelli, 2014; Gloor et al., 2017 b), or promoting innova tion within, and |
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across, organis ational boundaries (Wright and Dana, 2003; Dana, Etemad and Wright, 2008; Allen |
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et al., 2016) . These analyses , which also stress ed the importance of looking at the communication |
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styles and interactions taking place within the organizational boundaries, were often carried out |
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using traditional surveys or exploring e -mail networks. |
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Starting from the insights that emerge from past research, we developed t he present study with the |
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idea of offering a triple contribution: first ly, we present semantic and social network metrics that |
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can be integrated in existing financial models to increase their forecasting accuracy; second ly, we |
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give evidence to the value of transforming text data into words of networks, to extend the |
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informative power of traditional semantic analysis; third ly, we show how the market value of a firm |
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can be at least partially inferred by looking at the internal interactions among employees, when |
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considering an intranet social network. |
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An intranet is a private network based on web protocols , belonging to an organization, and usually |
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accessible only by the organization's members. The websites and software applic ations of an |
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intranet look and act just like any others, but the firewall surrounding an intranet fends off |
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unauthorized access and use (Beal, 2017) . An intranet forum is a social network among all the |
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people inside a company, in which employees can exchange text messages, share news and |
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comments, or multimedia files. |
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Enterprise intranets proved to offer important insights to business mangers (Eppler, 2001) , also |
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being a valuable tool to promote knowledge sharing (Hollingshead, Fulk and Monge, 2002), |
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facilitate HR activities and assess the internal mood (Sulaiman, Zailani and Ramayah, 2012) . From |
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an intranet social network it is often possible to extract knowledge maps (Eppler, 2001) . These are |
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graph s that provide a visual info rmation about knowledge sources and help evaluating strengths and |
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weaknesses of knowledge related assets . Intranet s are usefu l also from a Human Resource point of |
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view , to understand role s and skills within the organization, current activities and possessed |
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knowledge (DiMicco et al., 2009). 7 |
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To the extent of our knowledge, there is no research trying to combine words of networks with |
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semantic and social network analysis of an intranet social network, with the aim of forecasting the |
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stock price of a company. |
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2.1. Words and Networks |
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In this paper, we propose the analysis of a word co -occurrence network , as an addition to traditional |
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semantic analysis. There are several studies in this field, for example Diesner and Carley (2005) |
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showed how to detect social structure s through text analysis: by analysing major newspaper s they |
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managed to discover the social structure of covert networks – terrorist groups operating in the West |
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Bank. |
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Network s of words can be buil t in different ways, such as the analysis of words co-occurrence s in |
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single sentences or text excerpts (Dagan, Marcus and Markovitch, 1995; Bullinaria and Levy, |
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2012) . Centering resonance analysis was also proposed as a method for creating a network from a |
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text by analysing its centres (Corman et al. , 2002) . Other scholars used techniques based on |
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hypertext s (Trigg and Weiser, 1986) or semantic webs (Tim and Berners -Lee, 2006; van Atteveldt, |
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2008) focusing on specific words and links between online pages. |
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In our explorative study, we create d a word co -occurrence network , considering the messages |
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extracted from the intranet forum of a large Italian company and the co -occurrence of these words . |
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We investigated the position in the graph of the company brand – i.e. its centrality measures |
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(Freeman, 1978) – to better predict the company stock price (together with the use of more |
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conventional social network and semantic variables) . |
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3. Case Study |
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In our case study, we were able to fully crawl the intranet forum of a large Italian company , with |
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more than 50,000 employees, out of which about 8,000 were actively partic ipating to the online 8 |
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discussion s. As per agreed privacy arrangements, w e are prohibited from revealing more details |
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about the company. |
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In the intranet forum , employees were al lowed to post news and to comment on their own posts or |
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those of others, with no restrictions or pre -approval s from moderators. Starting from the analysis of |
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these interaction patterns, we were able to create a first Interaction Network , with n nodes |
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(employees) and m directed arcs (posts) . In this network, there is an arc originating at the node i and |
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terminating at the node j, if the social actor i answer s to a comment or a news of the actor j. This |
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network – built considering the news and comments posted between September 2014 and June |
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2016 , for a total of 94 weeks – comprises 8320 nodes and 48020 links. |
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In addition to studying the interactions among people working in the company, we also analysed the |
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relationships among the words used in the posts. In particular, we transformed the text of news and |
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comments into a Word Network , based on words co -occurrences (Dagan, Marcus and Markovitch, |
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1995; Bullin aria and Lev y, 2012) . In this network, nodes are representative of single words and arcs |
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connect words that co -occur in the text, either conside ring the words before, or after a specific one, |
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with a maximum distance of seven words. To put it in other words , for each co -occurrence within |
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this range we created a link going from one word to the other, with a directionality which respect s |
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the order of appearance in the text. To give an example, if a post is “Hello D olly”, then we would |
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have two nodes – “Hello” and “D olly” – with an arc originating at the first node and terminating at |
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the second one. Before building the word network, we corrected or removed the misspelled words |
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and removed the stop words - i.e. most common words in the language which usually do not contain |
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important significance - using the Python NLTK library (Perkins, 2014) . The resulting network is |
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made of about 16,00 0 words and more than 6,000,000 links. |
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When building networks of words, differen t techniques can be used and the maximum range for |
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considering a co-occurrence can vary. The choice of a maximum interval of 7 words provided the |
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best results in our case study; however , we maintain that the analyst should be free to adjust this |
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interval according to the specific context and dataset analysed. We also considered the possibility to 9 |
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simplify our network , by applying lemming or stemming algorithms to reduce words to their root |
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forms (Korenius et al. , 2004; Perkins, 2014) . However, a test in this direction produced no b etter |
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results than those obtained when we worked on the full network. |
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3.1. Study Variables |
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Considering the two networks described in the previous section, we extracted weekly measures for |
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a specific set of variables, representative of the social structure, the activity and the employees’ use |
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of language. To measure structural positions, we referred to well -known centrality metrics of Social |
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Network Analysis : betweenness and degree centrality (Freeman, 1978) . |
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Degree centrality measures the number of direct connection of a node in the network and |
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corresponds to the number of incident arcs, either originating or terminating at that node . |
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Group Degree Centrality quantifies the variability of individual degree centrality scores and it is |
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used to measure how much centralized a network is, and so how much dominated by a set of highly |
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central nodes. This measure reaches its maximum of 1 for a star graph (Wasserman and Faust, |
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1994) . |
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Betweenness Cen trality is a measure that reflects the number of times a node lies in -between the |
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shortest paths that connect every other pair of nodes (Wasserman and Faust, 1994) . |
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Group Betweenness Centrality reflects the heterogeneity of betweenness centrality scores of single |
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actors: for a star graph the value is maximum and equal to 1; for a network where each actor has the |
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same level of betweenness, this index is equal to zero (Wasserman and Faust, 1994) . |
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With regard to the interaction n etwork, we considered group level metrics with the intent of |
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investigating the full network activity, without focusing on single employees; for the word n etwork, |
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on the other hand, we focused on the structural position s of the node associated to the company |
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brand (which also co rresponds to the company name in the stock market) . Our aim was to test if the 10 |
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fluctuations of the brand in this network could be used as a predictor of the company stock price at |
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the end of each week (which is our dependent variable) . |
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To investigate the u se of language by the employees in the intranet forum , we carried out a |
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semantic analysis of the content of news and comments, mapping their average weekly level of |
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sentiment, emotionality and complexity. |
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Sentiment is a measure of the positivity or negativity of a text, calculated by using a multi -lingual |
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classifier based on a machine learning algorithm (trained on large datasets extracted from Twitter) |
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(Brönnimann, 2014) . A score of 0.5 represents a neutral sentime nt, whereas higher scores represent |
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a positive sentiment , and lower scores a negative one. |
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Emotionality measures the variation in the overall sentiment and it is calculated as its standard |
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deviation. If all the messages converg e towards a positive sentimen t score, the emotionality will be |
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low; by contrast , if there is a frequent alternation of positive and negative messages, the |
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emotionality will be high (Brönnimann, 2014) . |
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Complexity measures the distribution of words within a text, c onsidering as more complex the |
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words that are less frequently used in a specific context (Brönnimann, 2014) . Accordingly, a rare |
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word that is commonly used in a n intranet forum will not increase the general level of complexity. |
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As the last predictor in our study, we considered the weekly levels of activity as the number of |
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messages posted during a week ( Activity ) or the number of word co -occurrences ( Activity Words ), |
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i.e. the nu mber of links in the word network . |
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The semantic analysis, as well as the computation of the centrality and activity measures, were |
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implemented by using the software Condor1 and the package NLTK developed for the |
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programming language Python 3 (Perkins, 2014) . |
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1 www.galaxyadvisors.com/product -extended.html 11 |
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Lastly, to control for the general stock mar ket fluctuations, and the events which could affect all the |
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market, we included the FTSE MIB in the predictive models . This i ndex is the primary benchmark |
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for the Italian equity market; it captures about 76% of the domestic market capitalization. |
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As per agreed privacy arrangements, we could not collect other control variables, such as |
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employees’ age, gender, job role or busines s department. |
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4. Results |
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We combined the variables presented in Section 3 to see if they c ould be used as predictors of a |
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company price on the Italian stock market. Our aim is not to present a final model to make stock |
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market prediction s, but to draw the attention of scholar s on new variables that can be extracted from |
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a company intranet forum and easily integrated in more complex models, to improve the ir |
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predictive power. |
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We started our analysis by looking at the correlation s between our variables and the company stock |
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price , at various time lags. Specifically, we analysed the insights coming from the intranet forum |
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during the same week in which the stock price was collected (Current Week ) and in the two weeks |
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before (named respectively 1 Week Lag and 2 Week s Lag ), to see which time interval was more |
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informative (Table 1) . |
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12 |
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Table 1. Pearson’s correlation coefficients with stock price (N=94). |
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For an easier reading , we only reported the correlation coefficients of each variable with the |
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company stock price . As the table shows , there are relatively high correlation s of group degree and |
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group betweenne ss centrality wi th price . These correlations are negative at all lags, suggesting that |
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a more heterogeneous network, less centred on few dominant nodes, is a better indicator of higher |
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prices . As regards the semantic variables, sentiment is the only one which shows a significant |
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correlation (at lag 1 an d 2); this correlation is negative, probably reflecting the fact that a more |
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technical language is usually associated to news related to firm performance and to financial |
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events. As expected, FTS E MIB is highly correlated with stock price, proving its val ue as a control |
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variable. Lastly, the degree centrality of the company brand in the word network proved to be |
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significantly correlated with price: when the company name is more frequently mentioned in the |
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general discourse, in association with a higher number of different co -occurring words, the stock |
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price is higher. To consider possible autocorrelation ef fects , we implemented a first differencing of |
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the dependent variable and the Granger causality tests presente d in Table 2 . We considered up to |
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three -week lags, as suggested by the models diagnostics. |
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Current Week |
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Price Price 1 Week |
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Lag Price 2 Weeks Lag |
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Activity Words .421** .447** .426** |
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Activity (Interaction Network) -.128 -.121 -.180 |
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Group Betweenness Centrality (Interaction |
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Network) -.302** -.256* -.272** |
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Betweenness Centrality (Word Network) .142 .107 .283* |
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Complexity (Interaction Network) .091 .043 -.034 |
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Degree Centrality (Word Network) .369** .358** .330** |
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Emotionality (Interaction Network) -.165 -.194 -.148 |
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Sentiment (Interaction Network) -.185 -.230* -.264* |
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FTSE MIB .877** .863** .877** |
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Group Degree Centrality (Interaction Network) -.389** -.286** -.252* |
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*p<.05; **p<.01. 13 |
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Dependent: Price 2 |
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FTSE MIB 3.796 ^ |
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Activity (Interaction Network) .994^ |
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Activity Words 5.246^ |
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Group Betweenness Centrality |
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(Interaction Network) 3.984^ |
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Betweenness Centrality (Word |
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Network) 3.777^ |
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Complexity (Interaction Network) |
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5.806^ |
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Degree Centrality (Word Network) .023^ |
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Emotionality (Interaction Network) 1.543^ |
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Sentiment (Interaction Network) .831^ |
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Group Degree Centrality (Interaction |
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Network) 1.574^ |
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^p > .05. |
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Table 2 Granger causality tests ( Chi-squared values, N=94) . |
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As Table 2 shows , all our predictors can significantly granger -cause the company stock price , |
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suggesting that they could all be considered while making new predictive models. |
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As a last step of our analysis, we b uilt multiple regression models to forecas t the company stock |
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price and comment on the variance explained by each predictor (Table 3) . We did not use more |
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complex time series models – such as ARIMAX – because the autocorrelation of the stock price |
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was not significant in the Durbin -Watson test. |
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14 |
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Table 3. Stock price prediction: multiple regression models. |
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In the first models, we tested the contribut ion of predictors in blocks, avoiding to put together |
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measures for which we found multicollinearity problems ( e.g., group degree and betweenne ss |
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centrality). In Model 8, we combined all the significant variables which c ould better explain the |
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price variance . With respect to the time lags of each variable , we chose those who better performed |
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in the models. We found that the FTSE MIB alone explain ed 75.8% of the price variance. The new |
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predictors introduced by this study could increase the variance explained by 9.2%. In particular, we |
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found that negative sentiment at two weeks lag, higher activity in the word network at one week |
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lag, higher betweenne ss centrality of the company brand and lower group betweenne ss centrality |
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are all significant indicators of a higher stock price. Figure 1 summarizes our findings. |
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|
|
Model 1 Model |
|
2 Model 3 Model 4 Mod |
|
el 5 Model |
|
6 Model |
|
7 Model 8 |
|
FTSE MIB 5.34x10E - |
|
5** |
|
|
|
5.88x10E - |
|
5** |
|
Complexity (Interaction |
|
Network) Lag 0 |
|
.029 |
|
|
|
Emotionality (Interaction |
|
Network) Lag1 |
|
-.058 |
|
|
|
Sentiment (Interaction |
|
Network) Lag2 |
|
-.108* |
|
|
|
-.053** |
|
Activity Words Lag1 |
|
0.222** |
|
|
|
.076** |
|
Activity (Interaction |
|
Network) Lag 0 |
|
1.59x10 |
|
E-5 |
|
Group Degree Centrality |
|
(Interaction Network) |
|
Lag 0 - |
|
.409 |
|
* |
|
Group Betweenness |
|
Centrality (Interaction |
|
Network) Lag2 |
|
-.236* |
|
-.053* |
|
Betweenness Centrality |
|
(Word Network) Lag 0 |
|
.100* |
|
.114** |
|
Degree Centrality (Word |
|
Network) Lag0 |
|
|
|
.001* |
|
* |
|
Constant -.085 1.081* |
|
* .899** 1.081** 1.06 |
|
9* .963* |
|
* .922* |
|
* -.179** |
|
Adjusted R Square d .758 .046 .205 .069 .142 .032 .127 .851 |
|
*p<.05; |
|
**p<.01 15 |
|
|
|
|
|
|
|
Figure 1 . Significant predictors from the intranet social network . |
|
|
|
5. Discussion and Conclusions |
|
The objective of this paper was to study the employees’ communication behaviour on a large |
|
company intranet forum , to extract new variables that could be useful to forecast a company’s stock |
|
price . We did not mean to p resent final forecasting models but to give evidence to the importance of |
|
new metr ics that can be integrated in existing financial models to improve their accuracy . In this |
|
sense, our work has practical and theoretical implications for scholars, financial analysts and |
|
professional investors. |
|
By means of Granger causality tests, we proved the value of our metrics up to two -week lags. |
|
Subsequently, we included our predictors in multiple regression models to see whether they could |
|
improve the models accuracy with respect to the control va riable FTSE MIB. |
|
Our work is consistent with previous studies linking sentiment analysis and stock prices (Chung and |
|
Liu, 2011; Zhang, Fuehres and Gloor, 2011) : we found a negative corre lation of the stock price with |
|
the sentiment of messages posted in the company intranet forum . This cou ld be partially explained |
|
by a more technical language used in news which deal with firm performance (with a lower |
|
sentiment , for example, when compared to posts where employees discuss their leisure activities |
|
16 |
|
promoted by the company) . It could be the case that more irrelevant and positive messages are |
|
dominant in the network when there are no big events that can positively affect the stock price (this |
|
hypothesis was partially confirmed by an interview with the people in charge of monitoring the |
|
employees’ activity on the intranet forum). A more “democratic” network structure (lower group |
|
betweenness centrality) , less dominated by a smaller number of social actors, also proved to be |
|
predictive of higher prices. |
|
We offer a new contribution since we are among the first scholars linking a company stock price |
|
with the communication behaviours on its intranet forum . Even if the informative power of the |
|
analysis of the employees’ activity on enterprise intranets has been discussed in the past ( Eppler, |
|
2001; DiMicco et al., 2009) , its association with the market value of a company remain s mostly |
|
unexplored. We support the id ea that internal communication behaviours can affect and partially |
|
mirror business performance (Gloor et al., 2017 b), thus influencing a company ’s stock price. |
|
An additional contribution of this research is to present a new use of word co-occurrence network s, |
|
which helps financial predictions . We transformed the content of the messages posted on the |
|
intranet forum into a word co -occurrence network – where every node, representative of a specific |
|
word, was linked to the others based on th eir co -occurrences in messages (Dagan, Marcus and |
|
Markovitch, 1995 ); on this network , we studied the associations between specific positions of the |
|
company brand and its stock price. Looking at the patt erns interconnecting words, we saw that a |
|
higher activity – i.e. a denser graph with more co -occurrences – and a higher betweenness centrality |
|
of the company brand can predict higher prices. This last result could be representative of cases |
|
where the brand is more widely used, spreading ac ross many different news and comments and |
|
therefore being more central in the discourse . |
|
Some of the l imitations of this study are due to our impossibility to analyse more companies or |
|
different business sector s. Moreover, we could not consider the communication and the interactions 17 |
|
between employees which went through other media – such as emails, instant messaging apps, |
|
phone calls or face -to-face communication. |
|
To extend our results , we advocate further researc h to study the intranet forum s of more firms, also |
|
taking into account their size and business sector. It would also be important to consider larger time |
|
frames , to test other variables and network construction techniques , and to develop predictive |
|
models based on more complex machine learning algorithms (which already proved their value in |
|
the past). |
|
Due to privacy agreements, we could not access to more control variables to differentiate the |
|
interactions based on the individual differe nces of employees. Therefore, future researchers should |
|
consider taking into account factors such as employees’ age, gender and job role . Lastly , it could be |
|
interesting to study if more accurate models c an be obtained by isolating the communication taking |
|
place in specific business departments or geographical locations . Depending on the business |
|
context, one could focus the attention to the communication of employees working in specific |
|
business units (customer care, financial department, etc ...). |
|
|
|
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