M. Sinan Gönül

Decision Making and the Price Setting Newsvendor: Experimental Evidence*

We present an experimental study of the price-setting newsvendor problem, which extends the traditional framework by allowing the decision maker to determine both the selling price and the order quantity of a given item. We compare behavior under this model with two benchmark conditions where subjects have a single decision to make (price or quantity). We observe that subjects deviate from the theoretical benchmarks when they are tasked with a single decision. They also exhibit anchoring behavior, where their anchor is the expected demand when quantity is the decision variable and is the initial inventory level when price is the decision variable. When decision makers set quantity and price concurrently, we observe no significant difference between the normative (i.e., expected profit-maximizing) prices and the decision makers’ price choices. Quantity decisions move further from the normative benchmarks (compared to when subjects have a single decision to make) when the ratio of cost to price is less than half. When this ratio is reversed, there is no significant difference between order levels in single- and multi-task settings. In the multidecision framework, we also observe a tendency to match orders and expected demand levels, which subjects can control using prices.

Evaluating strategic directional probability predictions of exchange rates

The current paper aims to examine strategic predictions (with forecast horizons greater than six months) via the empirical probability (EP) technique. This technique was proposed initially to examine short-term tactical predictions (with forecast horizons less than three months), as set out in Pollock et al. (2005). The proposed procedure is based on the hypothesis that changes in logarithms of daily exchange rates follow a normal distribution over short horizons (of 10 to 30 days), but longer term forecast evaluation requires consideration of cumulative parameters consistent with changing means and standard deviations arising from primary and secondary trends. It is shown that ex-post EPs can be obtained for any predictive horizon above 30 days (e.g., 180 days) by using a combination of shorter (e.g., 20-day) Student t distributions. The procedure is illustrated using daily Euro/USD series from 4 January 1999 to 29 January 2008 to evaluate a set of Euro/USD directional probability predictions.

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.

Forecasting in health-service provision

Good decisions and policy depend on a reasonable degree of foresight; this in turn relies on a forecasting process that is well-integrated with the strategic management of an organization. There is, however, very little research into the forecast process within organizations generally, or health-services in particular. N.......Noting this gap, a framework for health-services forecasting research is proposed. Further, results from a study conducted within this framework are conveyed. This study reports a questionnaire on a group of administrators in Turkish health- service sector involving 39 chiefs of staff, 38 hospital directors, 37 head nurses, 12 managers from in-patient medical institutions, 55 administrators from the Ministry of Health, and 56 administrators from provincial health directorates. Data collected were analyzed using descriptive statistics and nominal logistic regressions. The results revealed that as forecast providers, the most importance is given to the credibility of technique and ease in using available data in selecting a forecasting technique. As forecast users, the highest importance is given to forecast provider’s credibility and expected predictive accuracy. Interval predictions were perceived to be the most useful prediction format, while point forecasts are considered the least useful. These assessments persist, irrespective of their experience, position, and background.