Over the last many weeks, Facebook seems to be missing lots of data in reports. For example, I had many Adsets that appeared not be working but when I turned them off, sales dropped. A week ago I noticed some data was showing up in FB Ads Manager days later. To solve this I have implemented GA on all sites and UTM tags in every Ad. Now I can see the effectiveness of every Adset and the sales data arrives quicker in Google Analytics, just minutes! Plus I can monitor all advertising traffic in one place, Pinterest, Perfectaudience, Twitter, Adwords, YouTube etc.
Text to paste into Google Analytics Setup:
Google URL builder: https://support.google.com/analytics/answer/1033867