How to choose your research organism

Despite August Krogh's famous admonition that a ‘convenient’ organism exists for every biological problem, we argue that appeals to ‘convenience’ are not sufficient to capture reasoning about organism choice. Instead, we offer a detailed analysis based on empirical data and philosophical arguments for a working set of twenty criteria that interact with each other in the highly contextualized judgements that biologists make about organism choice. We propose to think of these decisions as a form of ‘differential analysis’ where researchers weigh multiple criteria for organismal choice against each other, and often utilize multidimensional refinement processes to finalize their choices. The specific details of any one case make it difficult to draw generalizations or to abstract away from specific research situations. However, this analysis of criteria for organismal choice and how these are related in practice allows us to reflect more generally on what makes a particular organism useful or ‘good.’ •Uncovers how the scope of factors important for organism choice goes beyond mere ‘convenience’.•Identifies 20 criteria, clustered into 5 categories, for organism choice in biology.•The criteria offer a conceptual framework for reflecting on what makes an organism useful or “good” for research.•Criteria for organism choice are not independent but interact in context-dependent ways.•Biologists often use a process of multidimensional refinement to shape decisions regarding organism use.