Hi Abdul - if you have already asked this question on the Ovation Users' Group forum, you are probably getting a better answer over there since there are some good control experts over there; whereas I am definitely not a controls expert.

That said, some of your answer might be contained in the Operator Station Users Guide (OW360_20). Specifically, on page 8, there is a table listing the various reasons/causes for different quality states. That table is too long to list here. However, here is the general definition provided on page 88 of the manual:

Quality – The Ovation system supports four quality states: Good, Fair, Poor, and Bad, plus the condition Timed-out. Each indicates the condition of the point to the operator and to the algorithms.
The system can be configured to display an additional quality reason clarifier after the point quality description. If the reasons are to be displayed, you should configure the system to set the order of precedence for the quality reasons in addition to the text that is displayed for each reason. If multiple reasons are present, only the reason with the highest precedent displays. You can view all of the applicable quality reasons in the Value/Status tab on the Point Information window.

I hope this helps.