"Having seen patterns of complaints, common names coming up again and again, and then beginning to launch an investigation ourselves would alert very senior officers to a problem that could otherwise go under the table."
Last year's incident where the police were criticised by a judge for their conduct during an investigation into Nelson motorcycle gang the Red Devils was "not a bad example" of where the authority could have launched an investigation to shed light on police conduct.
Sir David also told the committee that the authority planned to increase the public reporting of its investigations.
He said the legislation governing the authority was framed in a way that seemed to imply that public reporting would be the exception.
Reports were to be issued only when it was in the public interest and the authority had tended to report on a few matters each year.
"I've taken the view from the start, in a pretty naive and innocent way, that we should report more publicly so that people can see what we do and why we do it and how we do it."
The authority had recently received advice from a senior QC about its legal ability to publicly report and there had also been a change in public attitudes and interest in the authority's work.
"It's likely that we will be reporting on all investigations unless there's an overwhelming private interest that's paramount."
Sir David said the change would have a positive effect on the authority's public profile which was quite low and therefore not being accessed as freely as it might be.
Other improvements to the authority's work and processes included work to reduce the time it took to complete inquiries.
It could be "very cruel on everybody, families, victims and police officers too" when investigations dragged on over years.
In line with moves by its English counterpart the authority is also looking at employing investigators who are not former police officers to counter perceptions inquiries are not completely independent.