Statistical reasoning in diagnostic problem-solving—The case of flow-rate measurements

Abstract

There are various methods for measuring flow rates in rivers, but all of them have practical issues and challenges. A period of exceptionally high water levels revealed substantial discrepancies between two measurement setups in the same waterway. Finding a causal explanation of the discrepancies was important, as the problem might have ramifications for other flow-rate measurement setups as well. Finding the causes of problems is called diagnostic problem-solving. We applied a branch-and-prune strategy, in which we worked with a hierarchy of hypotheses, and used statistical analysis as well as domain knowledge to rule out options. We were able to narrow down the potential explanations to one main suspect and an alternative explanation. Based on the analysis, we discuss the role of statistical techniques in diagnostic problem-solving and reasoning patterns that make the application of statistics powerful. The contribution to theory in statistics is not in the individual techniques but in their application and integration in a coherent sequence of studies – a reasoning strategy.

Keywords:

• Branch-and-prune strategy
• diagnostic problem-solving
• explanatory coherence
• hierarchical diagnosis
• root-cause analysis

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Notes on contributors

Jeroen de Mast

Jeroen de Mast is Professor of Statistics at the University of Waterloo, Canada, and also Scientific Director and Consultant at Holland Innovative in the Netherlands.

Stefan H. Steiner

 Stefan H. Steiner is Professor of Statistics at the University of Waterloo, Canada, and Chair of the Dept. of Statistics and Actuarial Science. He is also director of the Business and Industrial Statistics Research Group.

Rick Kuijten

 Rick Kuijten is a specialist for data and measurement systems at Water Board De Dommel, the Netherlands.

Elly Funken-Van den Bliek

 Elly Funken-Van den Bliek is a senior consultant at Holland Innovative, specializing in reliability and functional safety. She has extensive experience in the process industry as well as energy, high-tech, automotive, and aerospace, where she has worked with major companies to achieve substantial improvement in the quality and reliability of complex, innovative products.