Member number changes with status?
 

Sorry if this has been discussed before; I did a "Search" and couldn't find anything on this.

It appears my membership number doesn't stay the same from year to year. My first year I made Silver, then lost it. I then noticed my Silver number was not the same as the number now shown for me on the website.

Then recently I was given Platinum, and again the number changed. This is a bit confusing, although Lufthansa does something similar, and the old KLM Flying Dutchman program also had a different initial digit depending on your status.

Has anyone "broken the code"?

In my case, the seventh digit (and the last "check" digit) were all that changed. As a base member, my seventh digit was a "1" and as a Platinum it was changed to a "4". I went back and got out my old Silver card, and the seventh digit on that was a "2". Leads me to infer that the seventh digit is a "status" digit, probably as follows:

1 = base member;
2 = Silver status;
3 = Gold status; and
4 = Platinum status.

Since the last digit is a check digit, it is forced (compelled) by the rest of the member number, and probably has no significance (other than as a check digit).

This would seem to mean that my "real" membership number is the eighth through fifteenth digits.

Does anyone know if that's correct? And what, I wonder, is the purpose of the first six digits?

At the time of the sofitel privilege card, the number was changing every year (even without change of status) and this was really annoying. With A-Club, I thought that the number was not changing ? In my case, it never changed but I maintained the platinum status each year so maybe that's why ?

My number changed with status change, but apart from that, has remained the same. As mentioned, the 7th digit indicates the status level. Not entirely sure if the last digit is a check digit, but all of the other digits stayed the same.

This matches how my number has been changing.

Can certainly confirm that the seventh digit on my Plat card is 4.

Given the 2 posts above, I might as well add that, as a gold, my 7th digit is 3.

OK, that seems to confirm my inference:Now, does anyone have any idea why the first six digits, or what they do?

In my case, on all the cards, they are "308103". Same for everyone else, or are there different sets (perhaps indicating country of the member)?

Last year (and early this year), I went from Base Member to Plat.

Based in the US, my member number also starts with 308103 and I noticed the same change in the 7th digit noted. No other changes except the last digit (which as you mentioned, may be a check digit).

The last digit, for me, started at 8 and dropped by 2 for each increase in status (PLAT ended with a 2).

Now that you have mentioned it, that's the same for me as well.
Classic (base): 3081031xxxxxxxx3
Silver: 3081032xxxxxxxx1
Gold: 3081033xxxxxxxx9

I suppose when the last digit hits zero, it just starts again from the top.

Not really, since the apparent sequencing is a function of the formula used in creating the check digit, not an actual sequencing. In other words, the next member number issued after one ending in "9" would not necessarily end in "0", see this explanation of check digits.

To put it another way, you don't use all of the numerical sequence if you use check digits. This means that using 5 digit member numbers with the 5th number being a check digit, the number following "12345" would not be "12346" -- in fact it couldn't be, since there is really only one valid number in the series "1234x" and that is the one where the check digit (last digit) is "5" -- and so the next "sequential" number would be "1235y".

The fact that the check digit changes by 2 when the seventh digit changes by 1 gives a clue to the concept used in the formula, but not enough to be able to work out the formula itself.

I received a new card yesterday, upgrading me from silver to silver :rolleyes:, and it has a bit about the 7th number changing. In my case it has changed from a 4 to a 5, but both cards are silver.

Online it says I am gold.

So - the 7th number does indicate status, but there is a bit more to it!

My data points confirm 1 and 2 (although they weren't really in doubt) and adds "62" in spots six and seven for Club des Actionnaires Platinum status.

On the same US based account:

3081032 = initial Silver status (no naughty "free Gold" or "free Platinum" here);
3081031 = downgraded to base membership;
3081062 = Club des Actionnaires Platinum (6th and 7th digits changed).

Advantageplus

3084095xxxxxxxx3 = Advantageplus GOLD
3084096xxxxxxxx1 = Advantageplus PLATINUM

Additional data after Club des Actionnaires benefits were reduced to include Gold rather than Platinum status:

3081062 = Club des Actionnaires Platinum;
3081033 = Club des Actionnaires Gold.

In the dedicated CdA thread, zehbra reports that a move from CdA Platinum to 'standard' Platinum changed digits six and seven from 62 to 34. So it appears that 'special' numbers for CdA members may be a thing of the past.

My 7th digit is 6 on my platinum card.