Data quality is a key concern for artificial intelligence (AI) efforts that rely on crowdsourced data collection. In the domain of medicine in particular, labeled data must meet high quality standards, or the resulting AI may perpetuate biases or lead to patient harm. What are the challenges involved in expert medical labeling? How do AI practitioners address such challenges? In this study, we interviewed members of teams developing AI for medical imaging in four subdomains (ophthalmology, radiology, pathology, an…