Google Analytics is recording less than half the actual number of hits when used within an iframe

We have a website (domainX) which opens up within an iFrame from a website (domainY)

We have google analytics implemented on domainX including a goal tracking event set up in GA to see how many people complete an application form.

We have found that the traffic numbers are running less than half the actual numbers. We have confirmed this a number of ways a) comparing actual number of applications submitted compared to # goals reached in GA b) # of pageviews for domainX in GA compared to the number of pageviews of the host page in domainY c) analysis of server side logs

Has any one had experience in GA not reporting the correct information when insid开发者_StackOverflow中文版e an iframe?

The site is a business focesed site so the only thing we could put it down to was that corporate firewall of our customers could be blocking the GA call?

Any other suggestions?

When an iframe of domainY is included on a page of domain X, the cookies set within the iframe are considered third-party cookies.

Therefore, a higher percentage of users block those cookies by default. Specifically, iOS and Safari block third party cookies by default, and other users block them on an optional basis. Third-party cookies are less reliable for data for this reason.

(Third party cookies likely explain a part of it; the rest of probably a combination of all the reasons that GA generally undercounts compared to server logs. ie, bots, noscript, crawlers, and GA blockers.