Which statistics to look at to measure your deliverability on your campaigns?

When I say that deliverability is a complex and obscure art, there is one person at Badsender who never contradicts me, it's Marion Duchatelet! As soon as a term doesn't seem clear or logical to her, you can be sure that she will tag me or Jonathan to get explanations! And she won't let go of the steak until she assimilates the term! With this in mind, I set myself a challenge (a big one), which is to make her understand all the concepts of deliverability. So, I asked her to challenge me on a lot of subjects on which she had doubts or misunderstandings... And all this without any tongue in cheek!

For this first round dedicated to deliverability, Marion's questions were about campaign statistics!

Q01: Sebas, what statistics should I look at - apart from the deliverability rate - to make sure I don't have any deliverability problems?

Before I start giving you all my secrets... which aren't really secrets, I'll go back to the concept of deliverability rate. I had already written an article about it in November 2020 (https://www.badsender.com/2020/11/10/quest-ce-qui-se-cache-derriere-votre-taux-de-delivrabilite/) where I indicated that a router assumed that if the remote server did not send a return message (i.e. a bounce), the e-mail sent was considered to have been delivered! Which in the end makes this rate not really reliable!

To come back to the subject of your question, personally, when I have to make sure that an advertiser does not have a deliverability problem, I mainly focus on 2 rates: the bounces rate and the unique opens rate. I'll tell you why!

Bounce rate

I always start by analyzing the bounce rate, simply because it will tell me if there are potentially one or more ISP blocks. I say potentially because a bounce is listed in 2 categories: the hard (see permanent errors) and the soft (see temporary errors). If there is an active block, the bounces returned will be classified as soft by the router. By the way, some routers have a special category for blocking, they call this type of bounces Block bounces. You'll probably ask me how they know if it's a hard or a soft or a block bounce... They'll simply analyze for you each SMTP code received via the "return-path" address (see technical address found in the SMTP header of the e-mail) and categorize them. To be honest, there are often a few mistakes, so don't be surprised if you see bounces that are poorly qualified as a hard classified soft :' After all, bounce labels are not universal, each organization can set them up to their liking and they don't mind doing it :p

Going back to our bounce rates, if you see your soft/block bounce rate go through the roof, chances are you have a block! On top of that, if your router is so cool (like Sendinblue) and it also gives you a view of your bounces by destinationYou'll be able to see who's blocking you at a glance!

To learn more about bounce management : https://www.badsender.com/2016/12/14/delivrabilite-email-gestion-bounces/

The rate of unique openings

If I don't see anything special with bounce rates, I'll throw my lot in with unique open rates. You already know this, but if there is one rate that has been abused for several years, it is the open rate. Between spam filters that open "in number" and test links without interaction from the email owner, Gmail that truncates emails larger than 102 kb, Apple and its MPP which simulates openings without any action from the mail owner... the opening rates are getting less and less reliable! Despite everything, I like to consult them because it still indicates the trend of arrival of emails, an opening rate too low could indicate that an ISP delivers your emails as spam. Some routers like Sendinblue provide a traceable opening rate but, if ever I have a doubt, I do a good old seedlist test (basically a test on a panel of addresses that allows to measure the reputation of an advertiser at a moment T) to confirm or not the reputation impact. Here again, if your router provides you with statistics by destination, you'll quickly see if you have a delivery problem with an ISP!

Q02: When do you think I should be concerned about a statistical gap or point?

In the most beautiful and wonderful world of Care Bears, we should not wait to have a problem of deliverability to be interested in it. All the internal (router's dashboards) / external (free tools available) reputation indicators available should be followed regularly, that would avoid asking yourself a thousand questions the day you discover that everything is going wrong. As I told you before, the ideal is to follow all the indicators by destination, it would be a shame to look only at the global, an ISP with little volume could deliver in spam or be blocked without anyone knowing it. I say this because I have already experienced it during an audit 🙂

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As far as deviations are concerned, I'll take you as an example the monitoring I do for our clients, I've put some reference rates for each key indicator, if one of them is in orange or red, I go and investigate! I adapt my reference rates according to the average rates of the client and his type of business:

  • Deliverability rate : Good ' 95% ; 95% ' Average ' 80% ; Bad ' 80%
  • Opening rates: Good ' 30%; 30% ' Average ' 10%; Poor ' 10%

But the reality is quite different, as I am sometimes a psychopath, I make a first check as soon as the first % is lost, just to tell me that I did not miss something!

Q03: What should I pay attention to when I look at the details of hard, soft and block bounces?

What you should pay attention to when you look at the details of bounces, whether hard, soft or block, is their number. The percentage doesn't mean much, especially if you have volume fluctuations from one day to the next, your rates will easily increase if you have routed little volume. Ideally, you should compare these numbers over time on all your campaigns to detect problems. What I can assure you is that :

  • If you generate a lot of hard bounces, you should probably better secure your email address collection and/or clean your database of inactive addresses.
  • If you generate a lot of soft bounces, you should think about cleaning your database of inactive addresses before they become either hard bounces or spamtraps at the end of their life cycle!
  • If you generate a lot of block bounces, you should either consider changing your routing strategy to a dedicated IP if you don't, or seriously review your email marketing best practices, you must have missed this chapter 🙂

Q04: Why do you always want to look at the SMTP codes of bounces sent by ISPs/Webmails?

Ah ah! Very good question!!! I could give you my answer in one line: "Simply because it's the proof that an e-mail has not been delivered"! If it's a block bounce, the SMTP code will give me the reason for the block! I'll give you a few examples so you can understand better:

  • This is a block bounce sent by Orange: 550 5.2.0 Mail rejected. Mail rejected. OFR_506 [506]
  • And here is a block bounce returned by Outlook: 550 5.7.1 Unfortunately, messages from [xx.xx.xx.xx] were not sent. Please contact your Internet service provider since part of their network is on our block list (S3150)
  • And finally a block bounce returned by Gmail (yes it happens to them!): 421 4.7.0 [xx.xx.xx.xx] Our system has detected that this message is suspicious due to the very low reputation of the sending domain. To best protect our users from spam, the message has been blocked

On the other hand, to have access to this level of information, you may have to fight with your router unless it makes it available to you directly from your interface ... but it's rare! You will always be able to go through the support... provided that the support is reactive and that it can provide you the information, which is not always the case even in 2022!

Q05: Why is it good when a routing platform makes SMTP codes available?

There are several very good reasons for this!

The first one is simple... Imagine you see your bounce rate skyrocketing on your last campaign and you try to analyze the destinations a bit, in the end you see that Orange - your Top ISP - has a block bounce rate of 100%. If you don't have access to this level of detail that are the SMTP codes, I can tell you that you're going to remain hungry! You know there's a problem but you don't really know where it's coming from since you have no other information.

The second reason is vital! If you want to contact Orange, if you don't give them this SMTP code... Either they are nice, they will ask you for it, or you will always be waiting for a return from them even on the day of your retirement! Whether you want to contact Orange, SFR, Outlook, Yahoo, ... they will ask you ALL these famous SMTP codes! This is what will allow them to avoid looking for a needle in a haystack! Now you see the necessity to have them available right away: you detect the problem and you can contact the concerned ISP/Webmail right away. Otherwise, you'll have to go through the support and most certainly be patient if you don't have a premium subscription +++++ 😉

If you want a nice link where you can find a lot of SMTP return codes: https://smtpfieldmanual.com/

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