Scrum is the most popular Agile Framework. It is the lightweight framework that is used in dynamic changing environment. It is simple to understand, but difficult to master. Professional Scrum Master (PSM) and Certified Scrum Master (CSM) are the prestigious certifications in Scrum. Both are widely accepted and open book exams but there are some key differences as mentioned in the table below.
| PSM | CSM |
| Certification provided by Scrum.org | Certification provided by Scrum Alliance |
| PSM has 80 questions to be solved in 60 minutes | CSM has 50 questions to be solved in 60 minutes |
| Passing score is 85% | Passing score is 74% |
| PSM is more difficult | CSM is comparatively easier |
| PSM doesn’t require formal training | CSM requires mandatory training from registered education provider |
| PSM is valid for lifetime | CSM needs to be renewed every 2 years (Cost: $100) |
| PSM cost $150 | Depends upon education provider but is usually 2~3 times more expensive than PSM |
| After registration, there is only 1 opportunity to pass the exam. | After registration, there are 2 opportunities within 90 days to pass the exam. Each additional attempt costs $25 |
Before appearing for CSM or PSM check above differences and choose accordingly. Mention in the comments section your reason of choosing CSM or PSM. Check this article for similarities and differences between PMP and CSM.