The following article is taken from AgileInnovation written on March 10, 2014:
There are now two major* ScrumMaster certifications available. I’m often asked which is ‘better’ – so I decided to do a comprehensive trawl and summarize my findings here.
Firstly, I should state that I am a Professional ScrumMaster (PSM), and offer training courses for PSM – so with that in mind….
Certified ScrumMaster (CSM) from ScrumAlliance has been on the go for 14 years, since 2002. For its first 10 years there was no exam/assessment – once you attended a two day CSM course, whether you slept in the corner of the classroom or paid close attention, you graduated a ScrumMaster. It has always been expensive to attend CSM training, because there are a carefully limited number of trainers, and its very difficult and expensive to become a CSM trainer – you need to be ‘nominated’ by 5 existing trainers, pay $10K to register, etc. As a result, there are no trainers in Ireland, and the daily trainer fees charged are very high.
In 2010 the guys who created Scrum and founded ScrumAlliance left and set up an alternative body, scrum.org. Through scrum.org they offered a 60 minute online ScrumMaster assessment (85% to pass). Although they also offered ScrumMaster training, you didn’t have to attend one of their courses to qualify for the exam. This opened up the field to all training companies, thereby driving down costs. It also introduced a much more credible certification because to become a PSM you had to pass a rigorous exam. This didn’t reflect well on the ScrumAlliance certification, so they introduced an exam in 2012 – however their assessment is pretty half-hearted, allowing candidates up to 90 days (sic) to answer 25 of 36 multiple choice questions correctly (68%). And you still had to attend one of their expensive courses…
So although CSM has been 3 times as long in the market, PSM is rapidly gaining ground with about 120,000 (as of 2017) PSMs globally today. Its a much more rigorous assessment, much cheaper to get, and is backed by Scrums creators, Jeff Sutherland and Ken Schwaber.