Purity Index

This company was built around the idea that spam, scams and phishing attacks could be greatly reduced if all legitimate senders sent the high-quality email they are quite-easily capable of (see Protect Your Customers). But what is 'quality' in email terms? There isn't a simple answer..

Our first goal at SendForensics was the development of a quantifiable analysis and resultant metric for an email's deliverability i.e. the modelling of an email's likelihood of reaching any given inbox, passing the scrutiny of any given spam filter.

Sounds simple, but it had never been done before as the factors that determine email deliverability are highly complex and intertwined. Plus the correlations between deliverability and actual user-engagement are closer than perhaps one might expect.

It took a great deal of research, drawing from the company's specialist forensic fault-analysis background, but it eventually came together and the SendForensics Deliverability Score was born (and if you are one of our customers reading this, thank you for making the years of toil worthwhile!).

Now Deliverability is the primary concern for most marketers, serving as a decent benchmark for the 'quality' of an email in terms of their goals. If spam filtering-systems think it's peachy, then it's probably pretty good quality, right?

Well, for those in charge of corporate networks, ESPs, ISPs, and other high-volume senders, it's not quite enough..

What is the SendForensics Purity Index?

Picture one of the latest generation of phishing emails. In fact, no need, here's a recent one purporting to be from Amazon:

Amazon Email Sample "I didn't order this!" *Clicks on a link to investigate*..

This is not your run-of-the-mill spam email. It has been engineered to be highly-deliverable, whilst still carrying the inevitable nefarious payload (often a single link).

It's been sent from a hijacked machine (probably via botnet) so benefits from a reputable sending-infrastructure (no blacklistings and the authentications check out), and the spoofed sending address is plausible. The content is very well copied from legitimate Amazon mailings, with no obvious tell-tale spam-markers (such as mis-spellings etc).

So, given that it consequently registers a high Deliverability Score, can it be considered high-quality? Well, if you're coding for the spam-Olympics then yes, it's a high-quality phishing email indeed.

But, if you're in charge of a network, this is a very dangerous email to allow the sending of.

Enter the SendForensics Purity Index. This is a predictive metric measuring the legitimacy, or Purity, of an email using similar techniques to those that allow us to predict its deliverability.

It's important to note, this is indicating how legitimate the email actually is - not how legitimate it looks. As we have seen, the best phishing emails are frighteningly legitimate-looking to even the most technically savvy user.

I'm not even embarrassed to admit that every now and again, I receive one that has been flagged as abuse but resists my own manual scrutiny for longer than it should..

A Complete Analysis

So why not combine our Deliverability Score and Purity Score into one Ultimate Email Quality Metric? Tempting. After all, it would be tidier for UI/UX, probably more convenient for user-interpretation, and definitely easier for me to write about..

But unfortunately it's a no. It would reduce the efficacy of both metrics in fulfilling their quite separate purposes, which is ultimately no good for anyone.

So there you have it; a Deliverability Score and a Purity Score. Both addressing the needs of different use-cases, but together providing a measure of email 'quality' that can be confidently supported.

Purity Index - Now Available with Enterprise Deliverability Control (EDC)

EDC with Purity