Why Didn’t My Mail Get Scanned? Did it Get Delivered?
March 29, 2021   Dave Lewis

This is probably not the first time I’ve written about this, and unlikely to be the last.  Mail tracking is not a perfect science, so interpreting the results correctly is important.  Very rarely will you see 100% of mail scanned to delivery.  Let’s explore why.  What fun!

First the basics.  SnailWorks uses Informed Visibility(IV) from the Postal Service to get tracking data.  The IMb on mail pieces are scanned as they go through sorting equipment at the Postal Service, and as they are sorted we are sent data on that scan, which we use to build reports.  In addition to these piece scans, IV is also sending data on pallets, trays, sacks and bundles scanned.  These scans are linked to mail pieces by the eDocs that accompany a Full-Service mailing.

Piece scans are “passive” scans – they are created in the scanning process automatically as mail pieces go through a machine – no extra effort required.  Container scans require someone to manually scan the barcode on a pallet or other container.  

Using this combination of scans, we can generally track mail from when it arrives at the Postal Service until the carrier walks by the delivery address.  (Or hops, or skips – we can’t tell from the scan.)

It is not unusual for scans to be missing – there are a variety of reasons they may be, and other times where our business rules may not report a piece delivered, though the piece may have in fact delivered.

First of all, let’s make an immediate distinction between letters and flats.  They follow very different paths.  We’ll talk about letters first.

Letter Size Mail

Letter-size mail is sorted almost entirely by sorting equipment, so we get a lot of data points for every letter from induction to delivery.  Let’s look at why tracking results may vary.

If your delivery scan rate is 98% - 100%:  Good for you!  That’s as good as it gets.  The few pieces not scanned may have been pulled as a double through a sorting machine, so the bottom piece didn’t get seen.  It happens.  We also often see in mailings with this kind of scan rate that the “non-delivered” piece was forwarded – if it doesn’t get delivered to the original address, we don’t count it as delivered in our system.

If your delivery scan rate is 90% - 97%:  Still a pretty good rate.  You may want to check to make sure that the unscanned pieces are spread evenly through the mailing.  It might be just one area that had a problem, or just doesn’t have scanning equipment (We’re looking at you, Vermont!)  Also, if the piece is a self-mailer that’s got a lot of thickness, or is bigger than 6x9, you may bypass scanning in some facilities.

If your delivery rate is 70% - 89%:  Hmmm, should be better than that for letters.  In this range, we generally look at the dimensions of the mail-piece, and look for individual areas that may have delivery issues.  We also like to look at barcode readability.

If your delivery rate is 1% - 69%:  Have you given the mail enough time to be delivered?  Sometimes it takes longer than you expect.  If you have, we’ll look at how the job was set up – the wrong mail date or a late file upload can mess things up.  Let our Project Management team take a look.

If your delivery rate is 0%:  Something is wrong, assuming you have given enough time for the mail to deliver.  The barcode on the mail pieces may not match the values in the SnailWorks system, or the date could be wrong.  Project Managers can often help with these and redeem even the most hopeless of situations.  “Often” being the operative word.  Of course, it is possible that your mail is sitting on a truck or in the corner of a facility – but usually not (whew!)

Flat Size Mail

Tracking flats is much more complex than letters.  Many flats never go through a piece-level sorter, and as such are never scanned.  We need to get scans of the pallets and bundles in order to predict or indicate delivery.  Because pallet scans are not “passive” they may not happen – humans need to do them.  The Postal Service monitors this scanning, and there are still a lot of pallets that do not get all of their scans.  Mailing flats Full-Service is essential – if there is no eDoc uploaded, we will get no information linking pieces to containers.  Most “missing” flat scan data are a result of containers not being scanned. 

SnailWorks has been very active working with the Postal Service trying to improve flats tracking rates, and tracking flats is much more effective these days than it was even a couple years ago.  Still, performance can vary a lot, depending on the type of mail sortation.

Carrier-Route, or other 5-digit pallets:  These generally go to the Destination Delivery Unit (DDU) with the pallet intact, so there will generally be no direct piece scans, but if the pallets are scanned, and the mailing is Full-Service, the scan of the pallet will be “assume” down to the pieces on it, so we can follow its progress as the pallet moves along.  In best cases, we will get them tracked to where bundles are distributed to carriers.  In other cases, we may still get a last scan as mail arrives at the DDU, and be able to reasonably infer a delivery date within a day or two.  On average, our expectation for this kind of mail is about 60% tracked.  This does not mean the rest of the mail was not delivered!  It just wasn’t scanned, or we didn’t get a scan that we could definitively say represented delivery.

Other sortation levels – 3-digit; 5-digit; ADC; Mixed ADC:  These kinds of mail are much more likely to go through flat sorting equipment at a piece level, and be tracked to delivery – along with corresponding pallet and bundle scans to help provide a complete and accurate picture of delivery.  We typically see scan rates of 85% - 90% these.  It is not as high as letters, because there are still many areas that lack automation (that’s right, Vermont…it’s still you…) and flats bundles sometimes evade scanning.  Still, you should expect decent rates.

If you’re not happy with your scan rates, by all means call us, and we will help you figure it out.  The first things we’ll do, which I would advise, is drill down to the geographic breakdowns and see if the issue is widespread or local.  If it’s local, that helps in figuring it out.  We’re still scratching our heads on some, though.  Mail can follow a funny path.

Also, remember, we are talking about delivery scans here.  Even on flats, first scans are typically 99% or better, so you can establish that the mail is in the system.

Our experience is that the Postal Service delivers very close to 100% of all types of mail, as long as it is properly addressed.  Low tracking scan rates perplex us, but even in those cases of poor scans, you can get a good sense of when your mail is in the system and when it will be delivered.

We’re here to help!