Evaluating probabilistic forecasts of stock prices in a developing stock market

Recent literature on the accuracy of forecasting in financial markets reveals contradictory results. These discrepancies can be attributed to the differences in forecasting environments as well as the differences in forecaster expertise that are employed by the researchers. Since the use of point and interval predictions by themselves do not aid in explaining the various aspects of forecaster performance, probabilistic forecasting provides a better alternative that can be used to gain insight into forecasting accuracy in such settings. This study aims to test the effects of forecaster expertise and forecasting environment on forecasting accuracy. Accordingly, various aspects of forecasting performance are studied in a developing stock-market framework. © 1994

The effects of feedback and training on the performance of probability forecasters

An experiment examined the effects of outcome feedback and three types of performance feedback-calibration feedback, resolution feedback, and covariance feedback - on various aspects of the performance of probability forecasters. Subjects made 55 forecasts in each of four sessions, receiving feedback prior to making their forecasts in each of the last three sessions. The provision of calibration feedback was effective in improving both the calibration and overforecasting of probability forecasters, but the improvement was not gradual; it occurred in one step, between the second and third sessions. Simple outcome feedback had very little effect on forecasting performance. Neither resolution nor covariance feedback affected forecasters' performances much differently than outcome feedback. However, unlike outcome feedback, the provision of performance feedback caused subjects to manage their use of the probability scale. Subjects switched from two-digit probabilities to one-digit probabilities, and those receiving calibration and resolution feedback also reduced the number of different probabilities they used. © 1992

Provider-user differences in perceived usefulness of forecasting formats

This paper aims to examine potential differences in perceived usefulness of various forecasting formats from the perspectives of providers and users of predictions. Experimental procedure consists of asking participants to assume the role of forecast providers and to construct forecasts using different formats, followed by requesting usefulness ratings for these formats (Phase 1). Usefulness of the formats are rated again in hindsight after receiving individualized performance feedback (Phase 2). In the ensuing role switch exercise, given new series and external predictions, participants are required to assign usefulness ratings as forecast users (Phase 3). In the last phase, participants are given performance feedback and asked to rate the usefulness in hindsight as users of predictions (Phase 4). Results reveal that regardless of the forecasting role, 95% prediction intervals are considered to be the most useful format, followed by directional predictions, 50% interval forecasts, and lastly, point forecasts. Finally, for all formats and for both roles, usefulness in hindsight is found to be lower than usefulness prior to performance feedback presentation. © 2003 Elsevier Ltd. All rights reserved

Values and Risk Perceptions: A Cross-Cultural Examination

This article examines the relationship between values and risk perceptions regarding terror attacks. The participants in the study are university students from Turkey (n = 536) and Israel (n = 298). Schwartz value theory (1992, 1994) is applied to conceptualize and measure values. Cognitive (perceived likelihood and perceived severity) and emotional (fear, helplessness, anger, distress, insecurity, hopelessness, sadness, and anxiety) responses about the potential of (i) being personally exposed to a terror attack, and (ii) a terror attack that may occur in one's country are assessed to measure risk perceptions. Comparison of the two groups suggests that the Turkish participants are significantly more emotional about terror risks than the Israeli respondents. Both groups perceive the risk of a terror attack that may occur in their country more likely than the risk of being personally exposed to a terror attack. No significant differences are found in emotional representations and perceived severity ratings regarding these risks. Results provide support for the existence of a link between values and risk perceptions of terror attacks. In both countries, self-direction values are negatively related to emotional representations, whereas security values are positively correlated with emotions; hedonism and stimulation values are negatively related to perceived likelihood. Current findings are discussed in relation to previous results, theoretical approaches (the social amplification of risk framework and cultural theory of risk), and practical implications (increasing community support for a course of action, training programs for risk communicators). © 2012 Society for Risk Analysis

Wisdom of group forecasts: Does role-playing play a role?

Forecasting plays a special role in supply chain management with sales forecasts representing one of the key drivers for collaborative planning and decision making in the organisations involved. We review the important role played by judgemental forecasts in this area, focusing on group predictions. Noting the scarcity of research using group forecasts, we present the results of an experiment where consensus forecasts are elicited from structured groups with and without role-playing. Comparisons with groups without any assigned roles show that getting into tailored organisational roles does have a significant effect in the resultant forecasts. In particular, members of the role-playing groups show less agreement with consensus forecasts and display a strong commitment to their assumed roles and scripts. Furthermore, role-playing groups leave a higher percentage of model-based forecasts unadjusted and when they do make an adjustment, it is significantly less than the groups, whose members are not assigned roles. Differences between the role-playing conditions are interpreted as highlighting the importance of role framing on forecast adjustment and group forecasting behaviour. Future research directions are proposed to improve the accuracy and acceptance of group forecasts. © 2011 Elsevier Ltd

Judgmental adjustments of previously adjusted forecasts

Forecasts are important components of information systems. They provide a means for knowledge sharing and thus have significant decision-making impact. In many organizations, it is quite common for forecast users to receive predictions that have previously been adjusted by providers or other users of forecasts. Current work investigates some of the factors that may influence the size and propensity of further adjustments on already-adjusted forecasts. Two studies are reported that focus on the potential effects of adjustment framing (Study 1) and the availability of explanations and/or original forecasts alongside the adjusted forecasts (Study 2). Study 1 provides evidence that the interval forecasts that are labeled as "adjusted" are modified less than the so-called "original/unadjusted" predictions. Study 2 suggests that the provision of original forecasts and the presence of explanations accompanying the adjusted forecasts serve as significant factors shaping the size and propensity of further modifications. Findings of both studies highlight the importance of forecasting format and user perceptions with critical organizational repercussions. © 2008, Decision Sciences Institute

Cognitive and emotional representations of terror attacks: A cross-cultural exploration

A questionnaire measuring cognitive and affective representations of terror risk was developed and tested in Turkey and Israel. Participants in the study were university students from the two countries (n = 351). Four equivalent factors explained terror risk cognitions in each sample: costs, vulnerability, trust, and control. A single negative emotionality factor explained the affective component of terror risk representations in both samples. All factors except control could be measured reliably. Results supported the validity of the questionnaire by showing expected associations between cognitions and emotions, as well as indicating gender differences and cultural variations. Current findings are discussed in relation to previous results, theoretical approaches, and practical implications. © 2007 Society for Risk Analysis

Judgmental adjustments through supply integration for strategic partnerships in food chains

Despite significant attention to strategic partnerships among members of supply chains, there has been limited research in food supply chains where such partnerships can provide a competitive advantage through forecasting practices of time-sensitive food items in volatile business environments. The current paper aims to close this gap by examining manufacturers’ strategic partnerships with retailers, with a special emphasis on information sharing, integration, and collaborative forecasting of timesensitive products in food supply chains. Through Partial Least Square (PLS) analysis of survey data collected from 105 food manufacturers in Europe and North America, this research reveals the importance of strategic partnerships for satisfaction from forecasts generated for perishable, seasonal, promotional and newly-launched products in the food industry. Group forecasting and manufacturers’ external integration with retailers are found to be significant for strategic partnerships. In addition, our findings show that manufacturers’ internal integration is positively associated with group forecasting, external integration and judgmental adjustments. Our findings also reveal that information sharing with retailers facilitates consensus forecasts in group forecasting. These results provide unique insights to researchers and practitioners of human judgment in supply chain forecasting towards enhancing strategic partnerships in food supply chains

Professional vs. amateur judgment accuracy: The case of foreign exchange rates

Highly knowledgeable people often fail to achieve highly accurate judgments, a phenomenon sometimes called the "process-performance paradox." The present research tested for this paradox in foreign exchange (FX) rate forecasting. Forty professional and 57 sophisticated amateur forecasters made one-day and one-week-ahead FX predictions in deterministic and probabilistic formats. Among the conclusions indicated by the results are: (a) professional accuracy usually surpasses amateur accuracy, although many amateurs outperform many professionals; (b) professionals appear to achieve high proficiency via heavy reliance on predictive information (unlike what has been observed before, e.g., for stock prices); (c) forecast format strongly affects judgment accuracy and processes; and (d) apparent overconfidence can transform itself into underconfidence depending on when and how forecasters must articulate their confidence. © 2003 Elsevier Science (USA). All rights reserved

The relative influence of advice from human experts and statistical methods on forecast adjustments

Decision makers and forecasters often receive advice from different sources including human experts and statistical methods. This research examines, in the context of stock price forecasting, how the apparent source of the advice affects the attention that is paid to it when the mode of delivery of the advice is identical for both sources. In Study 1, two groups of participants were given the same advised point and interval forecasts. One group was told that these were the advice of a human expert and the other that they were generated by a statistical forecasting method. The participants were then asked to adjust forecasts they had previously made in light of this advice. While in both cases the advice led to improved point forecast accuracy and better calibration of the prediction intervals, the advice which apparently emanated from a statistical method was discounted much more severely. In Study 2, participants were provided with advice from two sources. When the participants were told that both sources were either human experts or both were statistical methods, the apparent statistical-based advice had the same influence on the adjusted estimates as the advice that appeared to come from a human expert. However when the apparent sources of advice were different, much greater attention was paid to the advice that apparently came from a human expert. Theories of advice utilization are used to identify why the advice of a human expert is likely to be preferred to advice from a statistical method. © 2009 John Wiley & Sons, Ltd