Sequential sampling schemes and other statistical techniques in quality of service business surveys

While there is a general consensus in the business community regarding the importance of quality service surveys in improving the company's business results, relatively little attention was devoted to the theoretical aspects of data analysis and modelling which can increase substantially the effectiveness of those surveys. Using the data from a real-life project, we present here the developments and improvements achieved in the three stages that ultimately yield the conclusions from the survey: the analysis of the historical data, the design of the sampling method for the current survey and the development of specific indices for differentiating among the units of the financial institution. The statistical techniques fitted to historical data helped both in assessing the relative contributions of the various aspects of service, the overall perceived quality of service, as well as in providing the theoretical grounds for reducing the size of the questionnaire and thus increasing the reliability of the received replies. The sequential sampling scheme designed for this survey was particularly suitable to address the managements concerns. Finally, the classes of quality service based on the quality indices developed in the project contributed substantially to the ability of the management to rank and reward differentially the branches of the financial institution.