ANON12, it's pretty easy. At the start of the season, the SOS would have set performance targets, just like any employer/manager does to their employees. These performance targets should be in line with the business plan and of course they should be SMART (sincere, measurable, accurate, reliable and timely) targets. Like any business, I would expect that one a year a performance appraisal be made against those targets.
So, what would I see as defining "one of the worst NBL coaches ever". I would say that one needs to look at what SMART targets can be established.
To start of with, win-loss ratio is important, but is more of an outcome than a target. It's like a business saying "we will aim for 10 LTI's this year" OK, lets have 10 volunteers to get injured and then we have achieved that goal.
Certainly when looking at performance, there are a number of things to consider and businesses often do a 360 degree review to get a full appreciation of how someone is going. At the end of the day, anyone's performance be it from sweeping floors to governing this great sandy land is essentially "plan, do, check, act" (PDCA)
Plan: Plan the delivery of the project or execution of the plan
Do: Actually delivery the planned activities
Check: How is the plan tracking? Is it getting implemented as expected?
Act: Make corrective actions to things in the plan that aren't working.
The P part of the cycle appears to be done well, the D part of the cycle is not bad, but I think if you ask fans where Marty appears to be falling down, the most common response would be somewhere in the C or the A part of the cycle.
If Marty's sole performance objective was "Make Finals", then he has failed dismally. I don't think that was his only business plan objective. However, do we see Marty smoking dope or playing up around town? No.