This contribution generalizes the work of Drexl and Haase about the so-called proportional lot sizing and scheduling problem which was published in 1995. While the early paper considers single-level cases only, the paper at hand describes multi-level problems. 1t provides mixed-integer programs...

This paper applies Kim and Warde’s (2004) stratified Warner’s randomized response model to Mangat and Singh’s (1990) two-stage randomized response model. The proposed stratified randomized response model has an optimal allocation and a large gain in precision. Hence, the estimator based on...

Based upon an empirical survey among the 200 biggest CPA firms in Germany an hierarchical modeling framework for audit-staff scheduling with three levels has been developed. For the second level, the so-called medium-to-short-term planning, a binary optimization model is introduced which is...