cef6aa11_sults____The_Questionmark_Blog__Cons
[Type of assessment] Observational [What it means] Observer watches participant doing normal work [Pros] Valid and reliable as it provides first-hand information about performance in real conditionsCaptures information about process and behavior not just outcomes [Cons] 
Risk of a ‘special performance’ as someone behaves differently whilst being observedWill not cover emergencies and other non-routine work Needs good planning
June, 2011 | Getting Results -- The Questionmark Blog
Cons