As the folks at the SEI are so fond of saying . . . it depends! Specifically it depends on what you mean by “consulting.”
There is a lot of hyperbole on this subject - with lots of so-called "experts" weighing in. Here's the answer.
The SEI takes conflict of interest very seriously and the Lead Appraiser’s Professional Code of Conduct requires us to report any real or perceived conflict of interest for every appraisal we conduct. As part of their QA Process the SEI reserves the right to further investigate any conflicts (or anything else for that matter) to ensure that appropriate behaviors were exhibited. This makes sense.
So, on the face of that very limited information, it would seem that a consultant might have a conflict of interest.
However, and this is a big HOWEVER (so wake up and pay attention!), not all consulting is the same, and the “type” of consulting you’re asking about matters if we really want to answer the question accurately (and be fair to both you and your potential Lead Appraiser).
I like to tell my clients that I don’t do anything. Yes, I literally tell them “I don’t do anything!” So why do they keep hiring me? Why have I had ten banner years in a row with some of the biggest names in the industry? Simple. I really don’t do anything. Well, I do advise them on how to be better process engineers (I’m kind of like BASF . . . I don’t make Processes, but I help you make Processes better…). I help them make complex decisions, tell them where the roadblocks might be, how much things might cost, help them to communicate their objectives, and so forth. So I guess I do something, just not what you might expect a “process consultant” to do.
Everyone and his brother claims to be a consultant these days. But being a consultant means more than being in independent performer. And being a professional consultant means helping clients succeed by helping them help themselves. (and not leaving too many fingerprints behind…). If you write processes, perform QA Audits, or code and run test scripts, you’re not a consultant – you’re a contractor. Sorry.
Many, many contractors believe they’re consultants. So many make this claim that clients now call contractors “consultants” – but most of the time they’re not. This further confuses the conflict of interest discussion.
Now back to your question…..
So, if you “consultant” is also your “process guy” – if he writes process descriptions, does the QA, runs your SEPG, or especially “prepares” your teams for appraisals (or anything that looks, feels, or smells like that), then no, it’s probably not appropriate to use him or her as your Lead Appraiser.
But if he or she guides you towards becoming a better process engineer, helps you understand the CMMI better, suggests what training you should take, gives you tips on being a better communicator, how to run your SEPG, facilitates some workshops, and generally helps you down the “Path to Greatness” where YOU decide what your processes and measures should look like, then it may* not be a conflict of interest – but the Lead Appraiser should still document it in the appraisal plan.
Just like anything else there are gray areas, so have an honest discussion with your Lead Appraiser about it.
One more thought. Your boss used the work “Audit.” A SCAMPI Appraisal is NOT an audit, it is an appraisal meant to identify strengths and weaknesses of your organization – which can be uncovered MUCH MORE EASILY if your Lead Appraiser knows a lot about your organization already. Bringing in a Lead Appraiser “cold” is a recipe for waste and disaster and a huge, unnecessary, self-imposed risk. Why would you do that?
After all, CMMI isn’t about “getting a level.” It’s about collaborating with people to make your organization better. Make it real.
* you may have noticed I've used the word "may" here several times. This is because every situation is different and has to be evaluated in context.