Newsletter KPIs that actually mean something (and why opens no longer do)
Four figures tell you whether your newsletter works: inbox placement (does it arrive where it can be read), click rate (does anyone do something with it), conversion (does it produce what you wanted) and complaint rate (are you annoying people). The open rate no longer belongs in that list: since mail programs preload images and fetch them through proxies, you count opens that never happened and miss opens that did.
Why opens mislead you
An "open" is measured through an invisible image in the mail. If it is fetched, that counts as opened. That mechanism is broken in two ways. For some years Apple Mail has been prefetching those images for users who enable privacy protection, whether the mail is read or not: those are opens that do not exist. Other programs and corporate filters block images by default or fetch them through a proxy: those are opens you do not see, or see at the wrong place and time.
Use opens at most as a rough trend within one audience. Do not base decisions about subject lines, send time or list cleaning on them.
KPI 1: inbox placement
Delivered means the receiving server accepted the message. Whether it then landed in the inbox, in Promotions or in spam, that server does not report. Yet this is the figure that determines all the others: a mail in spam is not clicked and does not convert. You approach it in two ways: with test addresses at the large providers (Gmail, Outlook, Proximus, Telenet) that you check with every send, and by comparing clicks per recipient domain. A provider where clicks structurally lag behind the rest is a provider where you are probably not in the inbox. Read more about that approach on our page about deliverability.
KPI 2: click rate
The number of unique recipients who clicked at least one link, divided by the number of delivered messages. This is a deliberate action that no mail program imitates, and therefore reliably comparable across campaigns. Two caveats. Some corporate filters automatically click links to check them for safety; you recognise them by clicks within seconds of delivery on all links at once. A good platform filters those out. And look at unique clickers, not total clicks: one enthusiastic reader clicking ten times is not ten readers.
KPI 3: conversion
What happens after the click: an order, a request, a sign-up, a download. This is the only figure you can link directly to revenue or objectives. Measure it by adding campaign parameters to the links in your mail that your website or webshop recognises, and by attributing the conversion to the campaign in your analytics or webshop system. A newsletter with a low click rate but a high conversion per click is often worth more than a newsletter that arouses a lot of curiosity and yields little.
KPI 4: complaint rate
The number of recipients who clicked "this is spam", divided by the number of delivered messages. Providers such as Gmail report this to the sending platform through a feedback loop or their postmaster tools. This figure is small in absolute terms but weighs heavily: it is the clearest signal providers use to judge your next campaign. If it rises, something is wrong with expectations (people did not know what they signed up for), frequency, or segmentation.
Two figures you do watch, but not as KPIs
The bounce rate and the unsubscribe rate are health indicators, not performance figures. They should be low and stable; a sudden rise calls for investigation. But calling a campaign "good" because there were few unsubscribes is setting the bar on the floor.
A dashboard that is enough
Per campaign, on one line: delivered, unique clickers, click rate, conversions, complaints, bounces, unsubscribes. Per recipient domain: delivered and click rate. Put those two tables side by side and you see at a glance whether a disappointing campaign is a content problem (click rate low everywhere) or a delivery problem (click rate low at one provider). The real-time 2Mail dashboard gives you delivery figures and clicks per domain; conversion comes from your own webshop or analytics.
An example
A webshop sees its newsletter opens fall over six months from high to middling and considers overhauling its subject lines. Click rate and conversion, however, stayed stable over the same period. What changed: a larger share of readers uses a mail program that loads images differently. There was no problem, only a broken meter. Whoever had steered on opens would have been tinkering with something that worked.
Frequently asked questions
What is a good click rate?
That varies too much by sector, list and type of mail to name one number. Compare with your own previous campaigns, and per segment. A service update to existing customers and a promotion to a prospect list cannot be compared with each other.
Should I ignore opens completely then?
For decisions, yes. For list cleaning, better combine them with clicks and purchase behaviour: someone who never "opens" according to your measurement but does order through your mail is not a dormant subscriber.
How do I measure conversion without a webshop?
Define what you want from the reader: a contact form, an appointment, a download. Each of those is measurable with a campaign parameter in the link. You will find more about the setup on our page about email marketing.