Probability Of PF Certificate Being Changed?

I've been noticing more and more stamps coming on the market with PF certificates dated from the 80's and 90's. Especially on items that were, at one time, a block of four. The seller points out which single is for sale and the buyer will get a copy of the original certificate. On the few that I've considered, I've checked the PF database for any newer certificate for the same stamp but haven't seen any.

My question is, has anyone bought a stamp with say, a late 80's/early 90's PF cert be sent in PF for a new one and have it come back with a major change? Does buying a stamp with an older certificate improve one's odds that it will come back basically the same opinion? I'm curious about other's opinion on this.

Qualifying the question a bit - I am talking about PF and NOT PSE. Personally I am not interested in numerical grading just authenticity. Thanks.

I have had a number of opinions change upon resubmission. Keep in mind that if a single is broken out of a multiple the certificate for a submitted single will not link back to the multiple certificate.

Checking the PSE database is a must. It has nothing to do with grading. PSE issues more regular non-graded certs than PF by volume. If you are looking for information though who cares if it is a graded cert or not. I see a lot of newer PSE certs that call out reperforation in particular that was not picked up by the PF. There is now technology that can detect things that were not seen 30-40 years ago.

There are some sellers that are known for "losing" newer certificates that are not favorable. These sellers l-o-v-e 80's and 90's vintage PF certs.

I've also had a number of PF certs changed on resubmission. The PF has no way of knowing if there is an older cert on a stamp unless the submitter discloses this on the submission form, and it may not make any difference in the opinion they render. A lot of damage could have been done to the stamp since it was last examined.

I also think the PF is also more likely to call out minor faults today than they did even 10-15 years ago. Whether this is because of new technology as rogdcam suggests, or if it's because of changing standards, I'm not sure - probably a both factors are involved.

I recently bought a stamp at a Siegel auction with both clean 2002 PSE and 2005 PF certificates. I asked for an extension and requested that it be submitted to the PF for a new cert. It came back from the PF with with a thin noted in the opinion. I don't know for certain, but I would presume that Siegel made reference to the previous PF certificate when they made the new submission.

Widglo, that's a little disconcerting seeing something from PF from 2005 (pretty current to me) come back as thinned. You'd think both the older PSE and PF would have caught that.

canyoneer, you missed what widglo said. Stuff happens to stamps over time. In other words, there may not have been a thin in that stamp in 2005. Recall the thread here about careful stewardship of one's stamps and the members who didn't care. Also recall the true story of the C3a that got eaten by a vacuum cleaner.

And the story of how almost ALL the C3a examples with a straight edge wound up in a glassine in Col. Greene's wallet for months, where they all got stuck together.

Older certificates CAN be extremely unreliable because of things that happen to stamps over time. And then there are the changing expertizing standards, experts, phase of the moon, season, day of the week, etc.

I agree and would say that unreliability is a significant issue. Certification organizations tout their service as a form of insurance; PF promotes it as "protecting your investment" and "the expertization process provides confidence". No one wants unreliable insurance.

Saying that certs have a shelf life, or that certification criteria evolve over time, or that different organizations give different opinions, or that technology and/or the knowledgebase drives changes in the status of a stamp's certification over time are all things that undermines confidence.

The same thing happens with auto insurance. One day when you finally need to use it they push back and balk at paying to repair your car. Most folks do not continue to use insurance services that are unreliable. The service is all about confidence and peace of mind.
Don