Inbound reporting tends to drown in activity counts. Strip it back and four numbers predict whether inbound demand becomes pipeline: how fast leads get a real response, what share of them deserve one, how many hand-raisers end up as meetings, and what each qualified meeting costs to produce. Everything else is commentary.
Speed to lead: fifteen years of audits, one conclusion
The research behind the famous "5-minute rule" is nearly twenty years old: the MIT and InsideSales.com study found leads contacted within 5 minutes were 21 times more likely to qualify than at 30 minutes. What is remarkable is what every audit since has found about actual behavior:
| Year | Study | Sample | What it found |
|---|---|---|---|
| 2007 | MIT / InsideSales.com | 15,000+ leads, 100k+ call attempts | 5-minute responses 21x more likely to qualify than 30-minute, 100x more likely to make contact |
| 2011 | Harvard Business Review audit | 2,241 US companies | Average response ~42 hours; 23% never responded; 1-hour responders ~7x more likely to qualify than slower |
| 2017 | Drift (now Salesloft) audit | 433 B2B SaaS companies | 7% responded within 5 minutes; 55% silent after 5 business days |
| 2020 | Workato study | 114 B2B companies | Average email response 11h 54m; roughly 1 in 5 never responded by email |
| 2022 | Chili Piper study | B2B software vendors | Responders averaged 4h 50m; nearly 30% never responded at all |
| 2024 | RevenueHero audit | 1,000 B2B SaaS websites | 63.5% never responded; responders averaged 1 day 5h 17m |
Two honest caveats. Most of these are vendor-run audits with an incentive to find slow responses, though each states its methodology and the independent HBR research agrees with them. And the oldest multipliers describe decay curves measured before modern buying behavior. Neither caveat rescues the headline: across fifteen years, the most common response to a B2B demo request has been silence.
The benchmark to set internally: first meaningful response in under 5 minutes, on every channel, at every hour. If that sounds impossible for a human team, that is the point. It is the core argument in our inbound SDR guide.
Qualification rate: how much of your inbound is real
Chili Piper's benchmark across roughly 4 million B2B form submissions found 14.1% formally disqualified, ranging from 6% to 23% by industry. RevenueHero's inbound benchmarks show qualification rates around 65 to 70% overall, with some software categories qualifying barely half. Translated: somewhere between one in seven and one in two of your form fills should never reach a rep.
Both numbers come from companies already running routing and scheduling tooling, which likely flatters them. The metric to own is your junk share: what percentage of inbound got disqualified, by whom, and how long it took. If nobody can answer that, reps are paying the triage tax silently.
Form-to-meeting: where hand-raisers leak
The same Chili Piper dataset puts form-to-meeting conversion around 30% as the industry baseline, rising to 66.7% with instant scheduling and 69.2% when a live call option is added. The delta is not persuasion; it is removing the gap between "I want to talk" and "we are talking." Every hour in that gap is where booked pipeline quietly leaks, which is why routing strategy and instant booking matter more than any follow-up cadence.
Activity and attainment: the human baseline
For calibrating expectations of a human inbound SDR function, the Bridge Group's B2B benchmark remains the reference: 3.6 quality conversations per rep per day, 63% of reps hitting quota, a 2.3:1 SDR-to-AE ratio, and median SDR-sourced pipeline of $2.8M a year. Useful numbers, with one structural caveat: they describe reps working business hours, while inbound arrives 168 hours a week.
The metric that ties it together: cost per qualified meeting
Speed without quality produces fast junk. Quality without speed produces slow excellence for buyers who already moved on. The metric that punishes both failure modes is cost per qualified meeting: everything you spend handling inbound, divided by the qualified meetings that actually land on reps' calendars.
It is also the fairest frame for the human-versus-AI comparison, because it counts what each option actually produces rather than what it costs per seat. The full cost side of that equation, salaries, loading, turnover, and the AI alternative, is in what an inbound SDR costs in 2026, and the working model is on the ROI page.
Common questions
What is a good speed to lead?
Minutes. The foundational research found a 21x qualification drop between 5 and 30 minutes, and every audit since shows most companies responding in hours, days, or never.
What share of inbound leads should qualify?
Benchmarks put formal disqualification at 14.1% at the median and a third or more in many software categories. Measure your own junk share first; it decides everything downstream.
What is cost per qualified meeting?
Total inbound handling cost divided by qualified meetings booked. It is the cleanest single number for comparing a human SDR function against an AI inbound SDR.