Table 3. Sample milestones for one of the subcompetencies within Critical Thinking Skills. Verbs in bold font indicate observable behaviors representing each stage of skill acquisition.

CRITICAL THINKING SKILLS	MILESTONES
	Beginning PhD Student	Advanced PhD Student	PhD Graduate	Early-Career Scientist	Science Professional
B. Design a single experiment (answer questions, controls, etc.)	Follow experimental protocols, seek help as needed, describe critical role of controls	Plan experimental protocol; include relevant controls; choose appropriate methods; troubleshoot experimental problems	Design and execute hypothesis- based experiments independently; evaluate protocols of others; predict range of experimental outcomes	Consistently design and execute experiments with appropriate controls; assess next steps; critique experiments of others	Teach experimental design; guide others doing experiments