What makes a task difficult? An empirical study of perceptions of task difficulty

Estimating the difficulty of tasks is imperative for project planning, task assignment, and cost calculation. However, little is known about how and for what purpose software practitioners estimate task difficulty in their day-to-day work. In this paper, we interviewed 15 professionals to understand their needs and perceptions when estimating task difficulty. We find that practitioners do estimate the difficulty of tasks for scheduling and prioritizing their work. Additionally, performing such estimation requires more than one metric, and across more than one domain (i.e. code metrics, process metrics, and task metrics). The use of metrics that encapsulate different aspects of a task allows developers to gain a holistic view of the task and its potential difficulty.