This chapter discusses the emotional labour of fieldworkers collecting phenotypic data and blood samples within the bipolar team at the Centre. It examines the ways in which increases in the collection of clinical data in ‘Big Biology’ involves a series of trade-offs and compromises. Large-scale psychiatric genetics can give the appearance of being a ‘data science’ driven by high-throughput laboratory processes and statistical manipulation of big datasets. The ‘natural resources’ of psychiatric genetics are the individuals and families with schizophrenia, bipolar disorder and other psychiatric disorders, who are recruited into large research projects. Historically, the clinical style of collecting and interpreting research data in psychiatric genetics has been an activity mostly conducted by clinicians. The emotional labour of fieldwork often involves aligning the scientific aims of psychiatric research with the social circumstances of the interview. Work in the clinical style of reasoning of psychiatric genetics is necessarily labour-intensive and messy.