Why do my search results differ from MOZ's rank tracker

[Brabian]

This is starting to happen a lot, i mean they weren't always an exact match but they differed by a few places. But now the gap between results I'm getting and MOZ's own rank tracker is quite large. For my keyword my page ranks on MOZ at 39 (it was 25 but has slipped down). Im seeing my page on page 1 locally and page 2 in incognito mode.

Now I understand there are other factors such as browser history, cookies, am i logged into gmail etc. Thats why I asked colleagues to use Internet explorer and they have nothing to do with SEO so their history wont affect the search. They report seeing it on page 2, even colleagues in a different office in a different city sees it on page 2.

I want to contact the department in question and share the good news that they've gone from none existent to 14th in what is a very competitive area. But MOZ's result has be second guessing whether I should.

Any ideas why the gap between results is so large?

Thanks

[Brabian]

Thank you all for coming back to me - since i posted this question it seems the results have now changed to something more accurate, maybe Moz was just a bit slow to update? I'll keep an eye on it. Thanks again to you all and apologies for the late reply I've been unwell.

[DonnaDuncan]

While the explanations offered make sense and I agree with them, you say it's happening "a lot". What's "a lot"? A couple of weeks? A month? More than that? I would think that the difference you're seeing should lessen if you're controlling for all the other influencing factors mentioned above. If not, it would seem as though there's something else at play.

[MonicaOConnor]

I would just add that no tool is perfect. Discrepancies happen. Keyword tools are meant to give you competitive analysis and show your progress over time. Location can be making differences, as well as the time of day the queries are happening. The snapshot you are given isn't necessarily inaccurate. There are so many factors that change the SERPs, it is hard to always have the perfect result.

[RyanPurkey]

Hello. Have you been using Google Webmaster Tools to get some ranking data as well? Plus Analytics to pull in some rough data on organic search volumes?  Are you using the same search engines in Moz's tools? (i.e. Google en-UK vs Google en-US?) Precise rankings are always going to be a bit difficult to report because of the many factors you listed, but the traffic from organic listings and to specific pages is much more manageable.

In the specific example you provide above, instead of congratulating them on their rankings you could let them know that their visits from search have gone from X to Y.