Process improvement is frequently, maybe even almost always, a component of service improvement. What I'm saying is that it's a bad idea to use process CSF's and KPIs as the desired outcome of an improvement project. I've come into client projects where the goal was something akin to "improve Problem Management to CMMI level 3". That's a noble purpose. The conversation might look like this.
Me: What is your project goal?
Client: To improve the services we provide to the business.
Me: Why do you need to improve services? Is there a specific business driver?
Client: Reach maturity level 3 in Problem Management.
Me: OK, how will you know when you've reached it?
Client: We have some internal targets set. Once we've reached those, we'll have an outside audit done.
Me: Great! What do you hope to achieve by doing this?
Client: I told you. CMMI level 3.
Me: No, what I mean is, what is the business driver causing you to do this now?
Client: The CIO talked about SOX compliance. There was a finding in our internal audit that needs to be addressed.
Me: OK, so the business driver is the remediation of a SOX audit finding?
Client: Yes ... (Sigh) ... but our outcome is to reach CMMI level 3.Then we discuss how maturity level 3 may have nothing to do with addressing SOX compliance. The client agrees with that, but says executives determined that CMMI level 3 would provide what they needed to remove the audit finding.
OK, now we're getting somewhere. It turns out that HOW achieving level 3 remediates the audit finding was never shared with the project team. All they know is that they need to achieve level 3 to remediate an audit finding.
Does having a process success factor, reaching Problem Management level 3 maturity, inherently improve the service provided to the business? No. There's an excellent chance it will even increase the cost of providing services. If we're going to increase costs, there better be an inherently clear business purpose for doing so, and that purpose should clearly provide more benefit than the added costs.
How many different process changes could you implement in order to achieve CMMI level 3? What does it mean to achieve level 3? How do we know that the process changes put in place in order to reach level 3 will actually resolve the audit finding? It's possible that your process changes help you achieve level 3, but do not address the audit finding. This is a recipe for disaster. The "service improvement" effort is based on a process CSF, which was selected in order to meet a compliance issue, and we know that making the necessary process changes may not even resolve the compliance issue!
This isn't a unique example. Plug in terms like "reduce incidents", "improve SLA achievement %" or just about any other process based metric you want.
There is no direct correlation between achievement of the process goal and improvement of services provided to the business.
You might end up improving services, but you could just as easily increase costs of providing services with no business-visible improvement in those services.
Process improvement is almost always part of service improvement. They compliment each other very well, but they are not the same thing. Before embarking on any sort of service improvement program, whether it is continual or one-time, make sure the desired business value is clearly defined before you start defining any process CSFs or KPIs.
Failure to do so dooms your program before it even starts.