SERPS appearing and vanishing every 15 days

[broadshout]

I have a regional careers website on a small seo retainer contract. I manage the google webmaster account and use moz tools to help keep pages finely tuned. The site has been experiencing a phenomena now for about 6 months whereby the SERPS (we work with around 10 keyphrases) are placed in top 5 positions and generate healthy google traffic and will then suddenly vanish. The cycle is roughly 1 - 2 weeks top page, followed by 2 - 3 weeks outside the top 5 pages of google results.

I contacted Google via webmaster central to ask for help and they simply confirmed that there were no penalties being applied and it was normal algorithm updates. I manage the seo for 20+ sites and have not seen this phenomenon elsewhere, not since the days of 'google dance' years ago.

Has anyone else had this experience ?

The SERPS always come back after a couple of weeks but then vanish again after a week or so this cycle has been ongoing for 6 months now and we have eliminated all symptoms we can think of.

Your feedback would be much appreciated in this matter.

[KevinBudzynski]

Very strange.  When checking the organic position, are you logged out of your google account? If the "true" organic position is on page 5 (or whatever), and when you are logged in your Google account you are on the first page could cause the position fluctuations but not the timing frequency (unles you do this every 15 days).  That is my guess.

[broadshout]

The positions are tracked by MOZ and google webmaster central. Checking via google.com is only for cross-reference and of course in a private session not logged in!

[KevinBudzynski]

First off, there is nothing wrong with checking results manually via Google and you did not state how you were checking them.  I was simply trying to help out on something you may have overlooked.

I have never received a thumbs down EVER (with close to 1,000 points). Why did you give me a thumbs down?

[Kingof5]

The positions Moz reports aren't always accurate. I've had it report a drop of 30+ positions for a keyword but we were still on the first page for it, and that's happened multiple times.

[broadshout]

There you go I've given you a thumbs up now. happy ? still doesn't answer my question though. I am asking if any one else has had the same experience. My ranking checks are accurate. They are cross-checked in google/moz/google webmaster central.