How are significant terms calculated?

Significant terms include interesting or unusual occurrences of words and phrases in subject lines. MailCharts groups subject lines into buckets (by brand, group, dates, and more!) and shows you the terms that make those buckets special. In our subject lines report, view significant terms for:

  • A brand (compared to brands in MailCharts or a group they are included in)
  • A group (compared to brands in MailCharts)
  • A time period (compared to the previous period or prior year)

Significant terms are calculated by comparing a foreground frequency (which is the frequency of the bucket you are interested in) with a background frequency.


How is promotion rate calculated?

Our promotion rate is determined by identifying how many emails a brand or group sends that contain a promotion. We detect promotions like dollars-off and percent-off discounts, buy-one get-one and free shipping offers in subject lines.


How is mobile optimization rate calculated?

Mobile optimization rates are calculated by detecting how an email renders at a pixel width of 400px — approximating the width of a mobile phone. The actual emails themselves are loaded into a browser and rendered in both a desktop- and mobile-width scenario. If the email itself responds to a width of 400px, it is identified as being mobile optimized. However, if the email gets clipped at the narrower width, the message is identified as not mobile optimized. Every email that MailCharts receives is tracked for mobile optimization. Mobile optimization rates are also available for each brand and group in our app.


What does it mean when an email passes or does not pass a DKIM or SPF check?

You can get 3 scores for DKIM and SPF checks:

  • Pass: 100%
  • Neutral: 50%
  • Fail: 0%

Here is what each of these mean (source):

  • Pass = ‘The message was signed, the signature or signatures were acceptable, and the signature(s) passed verification tests.’ This is the result you want to see. Everything worked perfectly.
  • Neutral = ‘The message was signed but the signature or signatures contained syntax errors or were not otherwise able to be processed.’  The message was signed, but it was not formed correctly. This is possibly a configuration error on the sending domain side.
  • Fail = ‘The message was signed and the signature or signatures were acceptable, but they failed the verification test(s).’ This means that the message had a signature, and the signature was formed correctly, but didn’t match the signature of the sending domain. This probably means the message was modified somewhere along the way.

In terms of how we get this data, this comes from our inbound email processor (which we use to process all of the emails we receive).