1. Facebook Measurement Announcement
In the review of 220+ metrics, Facebook found many errors in their calculating and reporting of those metrics.
Some are overstated, some are understated, none are billable metrics
3 key initiatives will also be announced:
The launch of a Measurement Council
Additional Third Party Verification
The introduction of a Metrics FYI Channel (to enable more regular communication on metrics)

2. Page Insights - Organic Reach
Organic Reach Miscalculation Summary
Issue: Summary number 7-day or 28-day organic page reach a simple sum of daily reach
Resolution: De-duplicate repeat visitors over 7-day and 28-day periods
Calculation Variance: de-duplicating repeat visitors over those periods on average:
7 day summary 33% lower
28-day summary 55% lower
Duration of Issue: bug has been live since May
Fix: next few weeks
“We've uncovered a bug in Page Insights. On one of our Pages dashboards, one summary number showing 7-day or 28-day organic page reach was miscalculated as a simple sum of daily reach instead of de-duplicating repeat visitors over those periods. However, the vast majority of reach data in the Page Insights dashboard was unaffected, including all the graphs, daily and historical reach, per-post reach, exported and API reach data, and all data on the Reach tab. The de-duplicated 7-day summary in the overview dashboard will be 33% lower on average and 28-day will be 55% lower; data in other fields is unaffected. This bug has been live since May; we will be fixing this in the next few weeks. It does not affect paid reach.”
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API overall bugs aren’t being fixed timely

3. Page Insights - Organic Reach Viewable
Page Organic Reach Counts Will Be Based on Viewable Impressions
Issue: page reach is defined as a person refreshing their News Feed and the post being placed in their feed
Resolution: a stricter definition that only counts reach once the post enters the person's screen (“viewable impressions”)
Calculation Variance: reported reach will be 20% lower on average
Duration of Issue: always
Fix: in the coming months
Additionally, we're making an improvement to Page organic reach to match what we've done for paid reach. Reach counts will now be based on viewable impressions. On Pages, we've historically defined reach as a person refreshing their News Feed and the post being placed in their feed. For paid ads reports, we've moved to a stricter definition that only counts reach once the post enters the person's screen (“viewable impressions”). With the stricter definition, we estimate that reported reach will be 20% lower on average. We'll provide an update to all Pages in-product and via the Metrics FYI blog when we make this change, which will happen in the coming months. To see screenshots of this example, please visit the blog.
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4. Video - Measuring Completions
When partners upload their videos to Facebook, the full video length is recorded, but when the video delivers to people's devices, the length of the video can sometimes be a fraction of a second shorter or longer. This discrepancy occasionally happens when the audio and video track don't line up, owing to differences between video players and devices. While someone may watch a video to completion on their device, the audio may continue to play for a bit longer. This particular issue caused us to undercount the metric ‘video watches at 100%' (previously named 'video views to 100%'). Moat found this and reported it to us. We are now updating how we read the video length to address this discrepancy. This update may result in roughly a 35% increase in the count of 'video watches at 100%.' For example, if 'video watches at 100%' were 1%, they will now be 1.35%.
Video Watches Under Counting
Issue: undercount the metric ‘video watches at 100%' (previously named 'video views to 100%')
Resolution: updating how read the video length to address this discrepancy
Calculation Variance: This update may result in roughly a 35% increase in the count of 'video watches at 100%.'
Duration of Issue: always
Fix: now
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5. Instant Articles - Time Spent
Instant Articles Average Time Spent Over-Reported
Issue: calculating the average across a histogram of time spent
Resolution: reflecting the total time spent reading an article divided by its total views
Calculation Variance: over-reported by 7-8% on average
Duration of Issue: Since August 2015
Fix: Now
Instant Articles is a way for any publisher to create fast, interactive mobile content on Facebook. We also provide publishers with insights to help them understand how their content is consumed. We’ve determined that the average time spent per article had been over-reported by 7-8% on average since August of last year. This was caused by a calculation error: we were calculating the average across a histogram of time spent, instead of reflecting the total time spent reading an article divided by its total views. We have now fixed this issue.
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6. Analytics for Apps - Referrals
Apps Referrals Overstated
Issue: counted both clicks to an app or website plus other clicks including clicks to view photos or video
Resolution: count clicks that went directly to an app or website only
Calculation Variance:
out of referrals 30% are actually clicks to consume content on Facebook
referrals have been overstated by approximately 6% on average
Duration of Issue: always
Fix: working to fix this now (vague on timing)
In our Facebook Analytics for Apps dashboard, one metric called “Referrals” is being overstated. This metric evaluates all Facebook posts produced by people via an app or website. We meant to count clicks that went directly to an app or website; however, we've also counted other clicks on those posts via the app or website, including clicks to view photos or video. We are working to fix this. Out of the referrals we currently report, on average about 30% are actually clicks to consume content on Facebook. For power users of this metric (top apps that look at this data in the dashboard most frequently), we found that referrals have been overstated by approximately 6% on average. Other measurements of referrals, such as those appearing in Facebook’s ads reporting tools, are unaffected.
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7. Interest Lists - Follower Counts
Profile Followers Will Drop
Issue:
Profile follower counts include the followers of interest lists
A profile's follower number could double count people who follow someone from a profile and through an interest list
Resolution: retire interest lists (claim it’s due to low consumer usage of interest lists)
Calculation Variance: Most profiles will see a drop in followers of less than 5%
Duration of Issue: always
Fix: not provided
Interest lists are a way to organize and view content on Facebook. Given low consumer usage of interest lists, we have decided to retire this feature, which will result in a drop in the total number of followers for profiles that created interest lists or were featured in lists. There are two reasons for this: 1) For people that created or were featured in an interest list, profile follower counts include the followers of the interest list; 2) People can follow someone from a profile and through an interest list, which means a profile's follower number could double count that person. This update does not impact News Feed distribution or Page Insights. The impact to profile follower counts will vary, depending on the number of interest lists the profile created and was featured in. Most profiles will see a drop in followers of less than 5%.
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8. Canvas Ad Clarification – Time spent
Canvas View Duration Metric
Issue: metrics includes traffic from offsite content on Facebook's in-app browser
Resolution: metric calculation to reflect that it excludes time spent outside Canvas (linking to offsite content).
Calculation Variance: did not provide
Duration of Issue: always
Fix: not provided
Clarified calculations: We’ll clarify some calculations to make sure they reflect how our products are being used by advertisers. For example, with the launch of Canvas in February, we gave advertisers the ability to create an immersive native experience on Facebook. Within Canvas, they can also link to offsite content on Facebook's in-app browser. While this experience is valuable to advertisers, the original intention of the Canvas View Duration metric was to capture time spent in Canvas. So we're clarifying the metric calculation to reflect that it excludes time spent outside Canvas (linking to offsite content).
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9. Video View Metric Update INSERT CLIENT IMPLICATIONS
Video Views Metric
Video View Metric Update
Issue: what was it before?
Resolution: video views metrics (3, 10, and 30 seconds) to include the term “aggregate,”
Calculation Variance: did not provide
Duration of Issue: always
Fix: not provided
More consistent definitions: We’ll also update our tips section and glossaries across all of our ads tools to make sure we are explaining our metrics in consistent ways (including noting which insights are estimates). For example, as we have rolled out new immersive experiences on Facebook like Canvas and lead forms, the link clicks metric has evolved over time to include clicks to those on-Facebook destinations, in addition to clicks to a website off of Facebook. We had updated the definition of links clicks in our ad creation tools, and we are now updating it across all of our ads tools. We're also clarifying the description of our video views metrics (3, 10, and 30 seconds) to include the term “aggregate,” so as to more clearly explain it's based on aggregate view time of at least the specified number of seconds.
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We've been working for several months to improve ads reporting, and today we’re announcing several updates intended to make information clearer and easier to understand. Some of the updates we're making are described below; for all we'll be updating our in-product definitions.
More descriptive names: We’ll make updates now and in the coming months to ensure our metrics are clearly named (e.g. “view content” → “website view of content,” and “video views” → “3-second video views”).
Clarified calculations: We’ll clarify some calculations to make sure they reflect how our products are being used by advertisers. For example, with the launch of Canvas in February, we gave advertisers the ability to create an immersive native experience on Facebook. Within Canvas, they can also link to offsite content on Facebook's in-app browser. While this experience is valuable to advertisers, the original intention of the Canvas View Duration metric was to capture time spent in Canvas. So we're clarifying the metric calculation to reflect that it excludes time spent outside Canvas (linking to offsite content).
More consistent definitions: We’ll also update our tips section and glossaries across all of our ads tools to make sure we are explaining our metrics in consistent ways (including noting which insights are estimates). For example, as we have rolled out new immersive experiences on Facebook like Canvas and lead forms, the link clicks metric has evolved over time to include clicks to those on-Facebook destinations, in addition to clicks to a website off of Facebook. We had updated the definition of links clicks in our ad creation tools, and we are now updating it across all of our ads tools. We're also clarifying the description of our video views metrics (3, 10, and 30 seconds) to include the term “aggregate,” so as to more clearly explain it's based on aggregate view time of at least the specified number of seconds.
Better categorization: We’re making it easier for marketers to select certain metrics to include in their reports. To do this, we're creating a way to customize the columns in reports to reflect how marketers set up their ads. This will let advertisers have a specific advertising objective map directly to the metrics we show, like checkouts, leads, or registrations.
*These efforts are long-term investments, and we'll continue to share updates on the Metrics FYI blog.