Descripancy jetpack vs. Google analytics

All stats tracking plugins collect and report information differently.

For example, Jetpack’s stats do not include visits from logged-in users by default. Many people find this useful, since recording your own visits may artificially inflate your stats. That might be one explanation for the variance between your other tracking plugins and Jetpack.

Jetpack also does not report visits in real-time. There is a bit of a lag between when visits occur and when they are reported in your stats. Additionally, there are certain search engine robots and spiders that Jetpack doesn’t count, and referrers that are considered to be spam by Akismet will not be reported either.

Since all stats plugins use different tracking methods, they will rarely (if ever) be perfectly sync in what they report.