Towards a Taxonomy of Programming-Related Difficulties during Maintenance

Empirical studies that investigate the relationship between source code characteristics and maintenance outcomes rarely use causal models to explain the relations between the code characteristics and the outcomes. We conjecture that the lack of a comprehensive catalogue of programming-related difficulties and their effects on different maintenance outcomes is one of the reasons behind this. This paper takes the first step in addressing this situation based on empirical evidence collected in a longitudinal maintenance study on four systems. Professional developers were hired to implement a number of changes in each of the systems. These activities were observed in detail over a period of 7 weeks, during which we recorded on a daily basis what specific problems they faced. The collected data was transcribed and analyzed using open and axial coding. Based on an analysis of these results, we propose a preliminary taxonomy to describe the programming-related difficulties that developers face during maintenance. Our intention is not to replace the existing categorizations/taxonomies, but to take the first steps towards an integrated, comprehensive catalogue by aligning our empirical observations and the earlier literature.