Facebook Graph API Ad Insights doesn't match Business Manager values

Question

I'm working on a report building tool that pulls data from Facebook Graph Api to display metrics on ads in an ad account. When I pull all the Insights from the account level the pixels purchases value is significant less than what is displayed in the Facebook Business Manager.

The query:

{act_id}/insights?fields=spend,action_values,website_purchase_roas&date_preset=this_month

Which returns the following data:

"spend": "5037.47",
  "action_values": [
    {
      "action_type": "offsite_conversion.custom",
      "value": "16049.98"
    }
  ],
  "website_purchase_roas": [
    {
      "action_type": "offsite_conversion.fb_pixel_purchase",
      "value": "3.186119"
    }
  ]

But the Business manager displays the Pixel Purchase value to be $17,315.53 and the Website roas to be 3.44. The Spend value seems to update in real time, sometimes even faster than the Business Manager page updates.

Is there some other value fields in the Insights edge that displays more purchases or is this a bug in Facebook's api?

Answer 1

You probably already checked but just for the sake of completeness, did you check if the attribution window in your business manager is set to FBs standard 28d post-click, 1d post-view window?

As you did not specify it in your API query, the API returns data in FB's standard attribution window and is represented under value.

You could add action_attribution_windows to your query &action_attribution_windows=['1d_click','1d_view'] to check these values as well.

This was the only times when we saw a difference in API pulled data and business manager data.