There's likely a number of reasons why Contextly Reports' numbers and Google Analytics' differ.
All though it sounds odd, web analytics is an art, not a science.
1. For example, if a reader partially loads a page may get counted as a pageview by one system but not the other.
2. Both Contextly and Google Analytics filter out "bot" traffic, but we may not filter out the exact same bots.
3. Some readers use plugins that block Google Analytics, but don't block Contextly and vice versa.
4. We may use a different time zone to calculate a day.
5. Contextly doesn't currently measure anything other than the posts it is installed on. So, for instance, we don't see homepage traffic or traffic to categories, tags, or privacy pages.
What's important in analytics is that they are *directionally* correct.
What do we mean by that? If our reports say there were 950 vistors to a story and Google registers 1000, that's just fine.
What's important here is that the numbers give a good sense of what's going on - and that they give accurate sense of things like scroll rates on posts and core audience.
If you are seeing a big difference between Contextly Reports and a different analytics system, do drop us a note at email@example.com.