From Unofficial BOINC Wiki
This is the potential Credit that you would be granted if other Participants validate your Result with an "identical" Result. When your Result is validated by a Quorum of Results created by the returned Results of other Participants you will be granted Credit and your Total Credit will be increased.
The current amount of Claimed Credit and the Work Units that were processed that have generated this Pending Credit amount are listed in your Results For User Page so you can monitor this value.
Remember, though, that the amount of Credit earned is determined by the Project Policies and therefore the amount of Credit that you claimed may not be the amount that is granted.
Quite simply put, your Claimed Credit is not the same as the Granted Credit.
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