The Email Metric That's Quietly Replacing Open Rates
There's a number that most email marketers aren't tracking, and it's probably a better predictor of their future deliverability than anything on their current dashboard.
Validity's latest benchmark report introduces what they're calling the "disaffection index," a composite metric that combines unsubscribes, complaints, and bounces into a single score. On its own, that sounds like a tidy new KPI for the analytics slide deck. But the reason it matters is more uncomfortable than that.
Why inbox providers flipped the weighting
Gmail, Yahoo, and increasingly Outlook have quietly shifted how they evaluate sender reputation. Positive signals (opens, clicks) still count. But negative signals now carry disproportionate weight in inbox placement decisions.
A campaign that generates a 2% click rate and a 0.4% complaint rate doesn't net out to a good sender in Gmail's eyes. The complaints hit harder than the clicks help. In one list we manage (roughly 85,000 subscribers, B2B SaaS), we watched deliverability drop from 97% to 89% over six weeks despite click rates staying flat. The culprit was a slow rise in complaint rates that nobody flagged because nobody was looking at complaints as a primary metric.
That's the gap the disaffection index is trying to close. Instead of monitoring three separate metrics and hoping someone notices when one trends wrong, you get a single number that moves when your audience starts pulling away.
The three signals that make up the index
Validity's 2026 benchmark report breaks it into three components:
Unsubscribes are the polite signal. Someone actively opted out. Most teams track this, though usually as a percentage of sends rather than as a trend line over time.
Complaints (spam button hits) are the loud signal. This is the one that damages sender reputation fastest, and it's the one Gmail weighs most heavily. The industry threshold that seems to trigger problems is around 0.3%, and a lot of senders are closer to that line than they think.
Bounces are the structural signal. High bounce rates usually mean list hygiene has slipped, which correlates with lower engagement across the board.
Combined into one index, these three create an early warning system that, from what I've seen, gives you about 4-6 weeks of lead time before deliverability actually drops. That's the difference between fixing a problem proactively and scrambling to recover a burned sender reputation.
What to do this week
Pull your unsubscribe rate, complaint rate, and bounce rate for the last 90 days. Add them together. That's your rough disaffection index. It's not exactly how Validity calculates it (they apply weighting), but it's close enough to be useful.
If the combined number is above 1%, you probably have a segment that's dragging down the whole list. Identify which sends generated the highest complaint rates and work backward from there. Often it's one specific campaign type or one segment that signed up through a particular acquisition channel.
And honestly, even if your numbers look fine right now, start tracking this composite weekly. The whole point is that it catches drift before it becomes a crisis. By the time your open rates drop or your emails start hitting spam folders, you've already lost ground that takes months to recover.
