A Qualitative Study on the Implementation Design Decisions of Developers

TL;DR

This study explores how professional developers make implementation design decisions, revealing that these choices are influenced by higher-level design considerations and involve a generally consistent but individually varied decision process.

Contribution

It provides the first detailed qualitative and quantitative analysis of implementation design decision-making processes among developers, highlighting their complexity and dependence on higher-level design factors.

Findings

Implementation decisions are influenced by requirements and architecture.

Developers follow a generally consistent decision-making structure.

No single decision process is universally followed.

Abstract

Decision-making is a key software engineering skill. Developers constantly make choices throughout the software development process, from requirements to implementation. While prior work has studied developer decision-making, the choices made while choosing what solution to write in code remain understudied. In this mixed-methods study, we examine the phenomenon where developers select one specific way to implement a behavior in code, given many potential alternatives. We call these decisions implementation design decisions. Our mixed-methods study includes 46 survey responses and 14 semi-structured interviews with professional developers about their decision types, considerations, processes, and expertise for implementation design decisions. We find that implementation design decisions, rather than being a natural outcome from higher levels of design, require constant monitoring of higher level design choices, such as requirements and architecture. We also show that developers have a consistent general structure to their implementation decision-making process, but no single process is exactly the same. We discuss the implications of our findings on research, education, and practice, including insights on teaching developers how to make implementation design decisions.