Between TransUnion, Equifax and Experian: is any agency more anti-deletion than the other agencies? I have two items to dispute: one I can prove is incorrect and the other an unpaid credit card that went to collections 7 years ago. Which agencies tend to deny disputes? I believe I only have to contact one CRA, so I want to make sure I contact the best one. Also, is it 7 years when bad debt falls off your report, or is it 7 years and several months?
Federal law (the "Fair Credit Reporting Act") requires the credit reporting agencies to temporarily remove disputed items from your credit report, and the reporting creditor is required to establish that the information either is or isn't valid. The reporting agencies themselves don't make the final decision on the validity of the item you're disputing. Either the creditor can or can't substantiate the item, and it's as simple as that. If the item can't be verified by the reporting creditor then it comes off your report -- otherwise it is put back on.
This is a great scam of the companies that say they can remove bad credit from your credit report. Their scheme is to challenge everything on your report, and for the next few weeks to a month, you have what looks to be a clean credit report while the creditors investigate and report back. But of the debts are valid, they come right back.
As Dai pointed out, the agencies don't do well at communicating with each other, so you might have to go through this process with each of them individually.
I had an issue where one of my 0%-interest credit cards hadn't been reported to any of the credit agencies for six months, which reduced my credit-score dramatically because it made it look like I was carrying a much higher balance than I really was.
I needed to raise a dispute with all three agencies directly, they did not inform each other of the correction. Fortunately it was an easy, fire-and-forget process: I filled out each agency's online forms, waited 30 days, and creditkarma.com showed the corrections the following week.