Yes. We hire Scrum Trainers, too, and sometimes, when we receive a quotation, we will use an easy 3-step process. The basic idea is that the top people in the industry have already chosen for us. You just need to be able to decipher the message.
The first thing you should check is the accreditation association this trainer is associated with. You have to know that becoming a Scrum Alliance, a Scrum.org, or a Scrum Inc. trainer is very hard because these 3 are top-tier accreditation associations. They care about their professional positioning. Therefore, becoming a trainer could be a challenging selective process that takes a long time.
Hence, only the competitive ones will be in, while the rest that cannot meet the stringent standard will try to get "certified" by other means so that they can claim their legitimacy.
In the US, there is a university called Harvard and another called MIT. If you're the top student, you'd like to apply to schools like these. It is very hard to get in, so I got my bachelor's degree elsewhere. It's still good. But I'm not Harvard or MIT. If you know what I mean.
Remember, only this 3: Scrum Alliance CST, Scrum.org PST, and Scrum Inc. RST. In the Scrum training industry, the rest are the rest.
The 2nd step is checking the trainer's standing in an accredited association. There are usually three levels:
Level 1 Trainer - The basic, accredited trainer.
Level 2 Trainer - The Scrum Fellows. They are selected because they are usually the best trainers in their association. They are usually terrific in their skillset and achievement. They are the premium product of that Organization.
Level 3 Trainer - The partner or the regional partner. Just like the accounting big 4 accounting firms, the partners and regional partners are usually the best they have. They usually represent the best of the best.
So, coming back to MIT again. Some students graduate with a GPA of 3.75 and above. They are the best of the very best. They are also students graduating with a GPA of 3.5 and above. They are incredibly versatile. And they are just MIT regular graduates.
So, clever buyers will not make a subjective decision to choose themselves but let the very best of the industry professional choose for you. You just need to look at the report card - their standing in their professional organizations and make a decision.
Once a potential trainer passes through our first two rounds of the elimination process, whoever we go with should perform well. Then, we can proceed to check his delivery technique and personality. We can then know how much we "click" with this person.
After all, we don't want to work with someone we don't like, right? And many things can make us dislike a person, including how he speaks, walks, eats, and sleeps.
These can be very personal and subjective. ;)