British Unions in Decline: An Examination of the 1980s Fall in Trade Union Recognition

The authors analyze establishment-level data from the three Workplace Industrial Relations Surveys of 1980, 1984 and 1990 to document and explain the sharp decline in unionization that occurred in Britain over the 1980s. Between 1980 and 1990 the proportion of British establishments which recognised manual or non-manual trade unions for collective bargaining over pay and conditions fell by almost 20 percent (from 0.67 to 0.54). The evidence reported demonstrates the importance of the interaction between the labour market, the product market, employer behaviour and the legislative framework in determining union recognition status in new establishments. The sharp fall in trade union recognition appears to be largely driven by a failure to achieve recognition status in establishments set up in the 1980s. These results, when taken in conjunction with recent changes in the nature of employment in the British labour market, seem to paint a bleak picture for unions and there appears to be no reason why the decline in union activity should not continue into the 1990s.

Revisiting activity sampling: A fresh look at binomial proportion confidence intervals

The Wald interval is typically used to assign confidence to the accuracy of activity sampling studies. It is known the performance of the Wald interval is poor, especially when the observed probability is near zero or one. The suitability of the Wald interval for activity sampling is not often discussed in the operations management literature; if it is, this is usually followed by inappropriate and incorrect advice. Herein, a range of alternative binominal confidence intervals for activity sampling is reviewed. A number of selection criteria are considered including achievement of the target nominal coverage probability, size of the interval, and ease of use and presentation. It is recommended that the Clopper-Pearson interval is used for activity sampling. A table of confidence intervals and sample sizes that is specifically designed to be used within a new activity sampling procedure based on the Clopper-Pearson interval is developed. Finally, pedagogical issues are considered

Revisiting rescheduling: MRP nervousness and the bullwhip effect

We study the material requirement planning (MRP) system nervousness problem from a dynamic, stochastic and economic perspective in a two-echelon supply chain under first order auto-regressive demand. MRP nervousness is an effect where the future order forecasts, given to suppliers so that they may plan production and organize their affairs, exhibits extreme period-to-period variability. We develop a measure of nervousness that weights future forecast errors geometrically over time. Near-term forecast errors are weighted higher than distant forecast errors. Focusing on replenishment policies for high volume items, we investigate two methods of generating order call-offs and two methods of creating order forecasts. For order call-offs, we consider the traditional order-up-to (OUT) policy and the proportional OUT policy (POUT). For order forecasts, we study both minimum mean square error (MMSE) forecasts of the demand process and MMSE forecasts coupled with a procedure that accounts for the known future influence of the POUT policy. We show that when retailers use the POUT policy and account for its predictable future behavior, they can reduce the bullwhip effect, supply chain inventory costs and the manufacturer’s MRP nervousness

Supply Chain Collaboration in Tourism: A Transaction Cost Economics Analysis

This paper explores inter-firm collaboration in a tourism supply chain via transaction cost economics using a single case-study method. We focus on supply chain collaboration between a hotel, and its food and beverage suppliers. The transaction costs found consist of the search cost and cost of quality checking. Search cost exists due to bounded rationality of the firm. This is influenced by asymmetric information. The cost of quality checking incurs because the firm perceives that its suppliers may behave opportunistically. It is revealed that trust could reduce transaction cost of the tourist operators

The order-up-to policy "sweet spot": using proportional controllers to eliminate the bullwhip problem

We develop a discrete control theory model of a stochastic demand pattern with both Auto Regressive and Moving Average (ARMA) components. We show that the bullwhip effect arises when the myopic Order-Up-To (OUT) policy is used. This policy is optimal when the ordering cost is linear. We then derive a set of z-transform transfer functions of a modified policy that allows us to avoid the bullwhip problem by incorporating a proportional controller into the inventory position feedback loop. With this technique, the order variation can be reduced to the same level as the demand variation. However, bullwhip-effect avoidance in our policy always comes at the costs of holding extra inventory. When the ordering cost is piece -wise linear and increasing, we compare the total cost per period under the two types of ordering policies: with and without bullwhip - effect reduction. Numerical examples reveal that the cost saving can be substantial if order variance is reduced using the proportional controller

Avoiding the bullwhip effect using Damped Trend forecasting and the Order-Up-To replenishment policy

We study the Damped Trend forecasting method and its bullwhip generating behaviour when used within the Order-Up-To (OUT) replenishment policy. Using z-transform transfer functions we determine complete stability criteria for the Damped Trend forecasting method. We show that this forecasting mechanism is stable for a much larger proportion of the parametrical space than is generally acknowledged in the literature. We provide a new proof to the known fact that the Naïve, Exponential Smoothing and Holts Method forecasting, when used inside the OUT policy, will always generate bullwhip for every possible demand process, for any lead-time. Further, we demonstrate the Damped Trend OUT system behaves differently. Sometimes it will generate bullwhip and sometimes it will not. Bullwhip avoidance occurs when demand is dominated by low frequency harmonics in some instances. In other instances bullwhip avoidance happens when demand is dominated by high frequency harmonics. We derive sufficient conditions for when bullwhip will definitely be generated and necessary conditions for when bullwhip may be avoided. We verify our analytical findings with a numerical investigation