User perspective in judgmental adjustments : nested adjustments and explanations

Ankara : The Department of Management, Bilkent University, 2007.Thesis (Ph.D.) -- Bilkent University, 2007.Includes bibliographical references leaves 202-219.The purpose of this thesis is to investigate the judgmental adjustment behavior of forecast users on externally provided predictions. "Nested judgmental adjustments" are defined as a series of revisions on a set of given forecasts. These adjustments are commonly used in practice to integrate judgment into forecasting processes. Explanations accompanying predictions may also influence forecast acceptance and adjustment in organizations. To study nested judgmental adjustments, explanations and user perspective, this research reports the results of a survey and three experiments. The survey is conducted with forecasting practitioners to enhance our understanding of the reasons and motivations behind judgmental adjustments, as well as to examine expectations of forecast users and perceptions of forecast quality. In addition, experimental studies are carried out to investigate the effects of structural characteristics of explanations and the presence of original forecasts on adjustment behavior. Results are discussed and future research directions are given.Gönül, M SinanPh.D

When providing optimistic and pessimistic scenarios can be detrimental to judgmental demand forecasts and production decisions

This paper examines the accuracy of judgmental forecasts of product demand and the quality of subsequent production level decisions under two different conditions: (i) the availability of only time series information on past demand; (ii) the availability of time series information together with scenarios that outline possible prospects for the product in the forthcoming period. An experiment indicated that production level decisions made by participants had a greater deviation from optimality when they also received optimistic and pessimistic scenarios. This resulted from less accurate point forecasts made by these participants. Further analysis suggested that participants focussed on the scenario that was congruent with the position of the latest observation relative to the series mean and discounted the opposing scenario. This led to greater weight being attached to this observation, thereby exacerbating the tendency of judgmental forecasters to see systematic changes in random movements in time series.</p

Çevirimiçi Alışverişteki Engeller: Cinsiyet ve İnternet Güvenliğinin Etkileri

In the latest technology era, the widespread usage of internet enabled individuals tointeract continuously and led to altered buying behavior patterns. Literature focuses onthe critical effects in the field. Among many antecedents to online shopping, previousstudies point out two important obstacles: (i) acceptance and tendency to usetechnology in accordance with gender perceptions and (ii) internet security problems.This study analyzes the impact of these two prominent factors on e-commerce utilizationby studying the effects of these factors through primary and secondary data; a surveydesigned specifically for this analysis and the cross-country data from Eurostat. Thefindings show that while internet security problems significantly impact online shoppingbehavior, the evidence is mixed for the impact of gender. The results of this paperprovide insights for a successful e-commerce transaction and identify importantobstacles to be avoided for an efficient e-commerce system. Güncel teknoloji çağında, internetin yaygın kullanımı bireylerin sürekli etkileşim içindeolmasını sağlamış ve farklı alışveriş davranışlarına yol açmıştır. Literatürdekiçalışmalar, bu alandaki önemli etkileri ortaya çıkarmaya odaklanmıştır. Bu bağlamda,çevrimiçi yapılan alışverişi etkileyen unsurlar arasında iki önemli engel göze&nbsp;çarpmaktadır: i) Cinsiyet algısına bağlı teknolojiyi kabul etme ve kullanma eğilimi veii) İnternetteki güvenlik sorunları. Bu çalışma, göze çarpan bu iki unsurun e-ticaretinkullanımına olan etkilerini Eurostat'ın ülkeler arası verisini kullanarak ve de buçalışma için özel olarak tasarlanmış bir anketin sonuçlarını analiz ederekincelemektedir. Bulgular, internetteki güvenlik sorunlarının çevrimiçi alışverişdavranışını oldukça etkilediğini göstermektedir. Cinsiyetin etkileri ise daha karmaşıktır.Bu çalışmanın sonuçları başarılı bir e-ticaret işlemi için gerekenler hakkında fikirvermekte ve verimli bir e-ticaret sistemi için kaçınılması gereken önemli engellerigöstermektedir

Contrast effects in judgmental forecasting when assessing the implications of worst- and best-case scenarios

Two experiments investigated whether individuals’ forecasts of the demand for products and a stock market index assuming a best or worst-case scenario depend on whether they have seen a single scenario in isolation or whether they have also seen a second scenario presenting an opposing view of the future. Normatively, scenarios should be regarded as belonging to different plausible future worlds so that the judged implications of one scenario should not be affected when other scenarios are available. However, the results provided evidence of contrast effects in that the presentation of a second ‘opposite’ scenario led to more extreme forecasts consistent with the polarity of the original scenario. In addition, people were more confident about their forecasts based on a given scenario when two opposing scenarios were available. We examine the implications of our findings for the elicitation of point forecasts and judgmental prediction intervals and the biases that are often associated with them

Antecedents and effects of trust in forecasting advice

Forecasting support systems (FSSs) have little value if users distrust the information and advice that they offer. Two experiments were used to investigate: (i) factors that influence the levels of users' stated trust in advice provided by an FSS, when this advice is provided in the form of interval forecasts, (ii) the extent to which stated trust is associated with users' modifications of the provided forecasts, and (iii) the consequences of these modifications for the calibration of the interval forecasts. Stated trust was influenced by the levels of noise in time series and whether a trend was present but was unaffected by the presence or absence of point forecasts. It was also higher when the intervals were framed as 'best-case/worst-case' forecasts and when the FSS provided explanations. Absence of trust was associated with a tendency to narrow the provided prediction intervals, which reduced their calibration. (C) 2012 International Institute of Forecasters. Published by Elsevier B.V. All rights reserved

Forecasting: theory and practice

Forecasting has always been in the forefront of decision making and planning. The uncertainty that surrounds the future is both exciting and challenging, with individuals and organisations seeking to minimise risks and maximise utilities. The lack of a free-lunch theorem implies the need for a diverse set of forecasting methods to tackle an array of applications. This unique article provides a non-systematic review of the theory and the practice of forecasting. We offer a wide range of theoretical, state-of-the-art models, methods, principles, and approaches to prepare, produce, organise, and evaluate forecasts. We then demonstrate how such theoretical concepts are applied in a variety of real-life contexts, including operations, economics, finance, energy, environment, and social good. We do not claim that this review is an exhaustive list of methods and applications. The list was compiled based on the expertise and interests of the authors. However, we wish that our encyclopedic presentation will offer a point of reference for the rich work that has been undertaken over the last decades, with some key insights for the future of the forecasting theory and practice