The renowned social media giants have added pretty much to their arsenal like ad measurement, filtration and reporting methodologies for Facebook news feed and RHS ad impressions.
These methodologies altogether, address how Facebook complies with the IAB ad impression Measurement guidelines, the MRC minimum standards and the MRC invalid traffic detection and filtration guidelines addendum (version 1.0, 15 October 2015). Facebook news feed and right hand column (RHC) is at present ascribed for served display ad impressions.

Facebook employs "General Invalid Traffic Detection" techniques as defined by the MRC's Invalid Traffic Detection and Filtration Guidelines Addendum.
Ad placements and their types:
Facebook has three chief ad placements that are under assessment for MRC authorization. Ads displayed in the News Feed runs in both desktop and mobile environments (web and app) as well in the right-hand column (RHC) in the desktop environment.
Ad manger of Facebook enables the advertisers to self help themselves by creating and running ads, target ads, setting those ads and configuring the budget for the ads as well for the reporting.
Advertisers, via marketing API and with the use of their own tools could programmatically access Facebook’s advertising platform. This enables developers to use all the same functionality as Facebook marketing tools within a custom solution.
Ad measurement metrics:
Facebook’s current reporting system counts the delivered impressions and measures in News Feed and RHC. The impressions are reported through Facebook’s reporting system, ads manager and also reflect the billable impressions delivered and measured via Facebook’s ad delivery system. All of this and few more updates have been mentioned in 8 Ways to Do Facebook Marketing.
Ad impression measurement:
Ad impressions displayed across both the platforms (mobile and desktop) in Facebook News feed and RHC, an ad impression instantly counts any part of the ad that appears on the user’s screen. (I.e. greater than zero pixels and greater than zero seconds).
A check that is based on JavaScript is performed every 100 milliseconds or a frame rate of 60 frames per second which determines whether the ad has contented the greater than 0 pixel and more than 0 seconds requirement for measurement or not.
If the check is a success, a 1x1 pixel is fired and the impression gets counted.

If the check fails, the 1x1 pixel is not fired and the impression does not gets counted.
It has to be brought to the note that, this additional check setup does not exist for certain platforms because Facebook couldn’t detect when the stories are coming on screen, so to tackle this, they fire the pixel as soon as they get rendered. Some feature phones does not hold up the viewport measurement methodology and rather take up a "rendered" measurement methodology. These platforms and devices only account for a small percentage of the number of ads served on Facebook.
Facebook allows third-party ad tracking tags on their ads but only to certain apps like DoubleClick, Atlas etc. But, all the ad servings are performed by Facebook via the Facebook ad server. No empty frame for dynamic ads serving is involved.
Offline measurement
If the user is offline while the impression event occurs, then the offline impressions get stored and resent to the user, when he/she is back online, however, this had to done within six hours of the impression event, or else the impression event would be marked as non-billable.
Compound tracking
As each impression event is individually recorded and measured, hence, compound tracking is not brought up into the use.
Auto refresh:
Facebook auto-refreshes ad impressions in the RHC placement on desktop browsers after a certain period of time, except when it finds that an individual takes actions, that might specify his/her interest in the ad (e.g. floating the cursor over the ad). The refresh gets activated, when the individual scrolls or resizes the Facebook window, so, no refresh occurs while Facebook is being loaded on a background tab or when the individual is interacting with other windows or applications. Auto-refresh ad impressions make up over half of the total RHC impressions.
Cache-busting:
Cache-busting is a technique which prevents a web browser from re-using an ad that has been already shown to the user and forces the browser to request a new ad each time the page refreshes.
Facebook uses http header of the cache control to prevent caching on dynamic pages. Adding on to this, the client impression timestamp is also included in the request (via the CTS parameter), which helps in reducing the caching in the same manner possible.
Data logging and processing:
Every call to Facebook’s http service produces a logging event that is developed through the stream processing infrastructure. These kinds of logging events get to the Facebook reporting service, and the data is then combined and stored in the Facebook data warehouse. On the basis of this combined data, customers can create and schedule their reports.
The impressions in the ad logs are counted as “raw” statistics. Based on a list of rules and outputs the raw data as annotated logs, Facebook processes the raw logs, flags some of the events as non-billable.
Limitations
Caching: Facebook utilizes appropriate cache-busting techniques; however, conquering all caching is not possible.
Abandonment: Abandonment is a known measurement limitation; however, due to Facebook's technical measurement methodology of not recording the ad impression until it enters the viewport, the impact is believed to be insignificant.
Ad blocking tools (desktop only): Facebook has implemented measures that are designed to prevent ads blocked via AdBlock and AdBlock Plus from being measured as billable impressions (but they may still have an insignificant impact on reported metrics as these tools are constantly evolving).
Image rendering disabled (desktop only): Browsers with images disabled (desktop and mobile web) may result in ad impressions and feed impressions being measured that did not have the opportunity to be seen.
JavaScript disabled or incapable browsers (desktop only): The ads visibility on Facebook browser-based products rely on JavaScript to be enabled. Internet Explorer versions 7 and previous are also not supported.
Other technology issues
Google's Chrome browser has some pre-rendering functions that might exaggerate desktop feed impressions and RHC impressions. (Desktop only)
Facebook's News Feed impression measurement does not consider the assignment of other windows that might be open on the user's screen. As a result, if a user is about to place another window over an ad (or even move the browser window off screen), Facebook will not be able to detect this. (Desktop only)
Some feature phones do not support the viewport measurement methodology and employ a "rendered" measurement methodology (as noted above).
A user's connectivity is not always consistent or persistent, especially in mobile environments. In order to create a seamless user experience, we batch-fetch several posts at a time, ensuring that ad copy appears for all ads, even if images are still loading due to low connectivity. In situations where the ad is partially loaded, ad impression measurement is counted when any part of the ad appears on the user's screen (i.e. greater than zero pixel and greater than zero second), including ad copy.
Partner qualification control and material business relationship
Facebook acts as both the “publisher” and an “ad server”, as a result of which it doesn’t maintains the material business partner relationships with organizations that are a part of the transactional chain associated with serving, capturing ad actions or enriching ad impressions or audience measurement. To add on, Facebook does not “gets hold of” or purchases traffic.
A valid Facebook account is required in order to kick off the ad delivery on Facebook and all the ads must be associated with a valid Facebook Page that an advertiser chooses or creates to represent its business. Clients must agree to Facebook's Advertising Policies before placing ads. Ads undertake the content review procedures and are checked for conformity with Advertising Policies prior to ad delivery. Facebook's prime patrons are the advertisers or advertising agencies who purchase ad serving services and utilize the Facebook platform.

Filtration methodology
Facebook utilizes techniques based upon the identifiers, activity and patterns based in data in the log files, they also utilize data from the Trustworthy Accountability Group (TAG) and Interactive Advertising Bureau (IAB) in an attempt to sense and eradicate invalid activity, including but not limited to know and suspect any non-human activity or suspect any invalid human activity. However, because identification and intent cannot always be known or discerned by the publisher, advertiser or their respective agents, it is unlikely that all invalid activity can be identified and removed from the report results.
Robot instruction files
Facebook instructs robots via robots.txt to instruct them that, they should not follow or index any links within the domain from which the robot.txt file was retrieved. The robot instruction files are present in all tracking web server instances.
Identification of non-human activity
Facebook uses the IAB robots blacklist and TAG Data Center IP list to eliminate non-human and untrue activities from reporting. The IAB and TAG lists are evaluated quarterly, and a Facebook user agent blacklist is updated accordingly. Browsers that can be recognized as bots are barred from being able to log billable impressions.
Internal traffic
Facebook filters impressions from Facebook’s internal locations. Facebook compares an IP address against the entire list of Facebook IP addresses that is maintained by Facebook’s operation team. The operations team adds/removes IP ranges where Facebook stores internal traffic generated when it tests its production systems under test campaigns. The test data is stored in test database and is completely isolated from customer’s data.
Activity based filtration:
This is determined through analysis of incoming events in association with the identified user source and window of time in which the events took place. If the incoming event from a single user source goes beyond from a distinct verge, within the given amount of time, subsequent events would get logged but will be marked as non-billable and will not be reported.
How to detect and filter invalid impressions
Numerous systems are used by Facebook to detect and remove General invalid traffic, e.g. impressions generated by bots, as well as auto-checking for adware, malware, spam accounts, fake accounts, etc.
All the filters that are used by Facebook to remove invalid traffic are constantly supervised and reviewed, and accordingly the filters are updated.
The tools and techniques to recognize fake and malicious accounts are constantly monitored and assessed by devoted teams at Facebook. Formal reviews are carried out, in which the precision and accuracy of their methods are evaluated.
The methods used by Facebook are executed both at the impression level and the user level (i.e. a given impression may be marked as non-billable or a given user may be removed from the network if deemed malicious).
Data consistency and accuracy filtration
Facebook takes in various checks to ensure the precision and uniformity of the data.
Time check: Impressions that originated more than a certain time frame are excluded from further processing.
Activity frequency capping: Impression requests that exceed a certain number per hour are marked as non-billable.
Reporting of count discrepancies
The filters described above affect the impression counts and helps in distinguishing between genuine traffic and invalid traffic.
Data Reporting
Facebook help center has a dedicated section on reporting within ads manager, the ads manager includes the list of preset reports, available columns for reporting and how to schedule delivery of reports.
Quality assurance
Facebook has developed tools to run end-to-end data integrity and consistency checks for quality assurance purposes. Additionally, Facebook has a set of back-office tools that enables the Facebook staff to monitor activity trends. Facebook also runs checks between raw log files and the data warehouses to detect any discrepancies between the data sets.
Data re-issue/ ad refund
The verdict to provide credit or reimbursement is made on a case-by-case basis and depends upon the facts and circumstances of that particular issue. In the event that a credit or refund is provided, advertisers are notified through Facebook’s platform; however, there are circumstances in which the sales team would contact the advertiser directly.
Policies of data retention
Facebook's impression data retention policies vary but meet up with the minimum standards required by these guidelines. Customers could run and download reports against this data, though they are responsible for storing older reporting data. This policy is subject to change.