Short answer: The Signal Gap, a term Radius Hire introduced in The Radius Papers 01 (2026), is the distance between what a hiring decision rests on and what predicts the outcome. Evidence-based hiring starts by mapping it for one role: list the requirements, record the evidence held for each when the decision is made. The result describes a process, not a candidate.
Why do frontline hires fail even when the CV looked right?
Sometimes the answer has little to do with the candidate, and a lot to do with what the process actually knew when it said yes.
Picture a distribution centre outside Tilburg on a Tuesday morning. Two forklift seats are open. A third became empty on Friday, when a new starter did not come back. By Thursday an offer has gone out. The evidence behind that offer is a one-page CV, a fifteen-minute phone call and a start date.
This scene is a composite, not a documented case.
Nobody in that scene did anything careless. The market is tight, recruiter hours are limited, and good candidates do not wait long. But the offer still commits real money. The useful question is not "was this a good hire?" It is "what did we actually know when we decided?"
Key takeaways
- The Signal Gap is the distance between what a hiring decision rests on and what predicts the outcome.
- Evidence has five levels: verified, demonstrated, structured, claimed and not covered.
- Most hiring metrics look back at outcomes. The Signal Gap looks at the decision itself, at the moment it was made.
- The gap tends to be widest in frontline hiring: key requirements are not on the CV, many applicants have little formal experience, and key checks often come after the offer.
- It is an audit of a process, not a score for a candidate, and not a benchmark between employers.
On this page: Why the Signal Gap matters · What is evidence-based hiring? · What are the five levels of hiring evidence? · Why is the Signal Gap often widest in frontline hiring? · A different way to look at hiring quality · Worked example · Can the Signal Gap be scored? · How do you map your own Signal Gap? · FAQ
Why the Signal Gap matters
A frontline hire is a large decision, even when it is made quickly. One full-time seat in Dutch transport and storage costs about €75,000 a year in labour (CBS: €44.40 per hour worked in 2025, times about 1,700 hours). Entry-level seats cost less. It is labour cost, not the cost of a bad hire.
Two hiring processes can take the same time and produce the same number of hires, yet rest on very different evidence. From the outside they look identical. The Signal Gap makes the difference visible. It turns a general worry, "we hire on gut feeling", into a specific list: which requirements rest only on the candidate's word, and which are never checked at all.
What is evidence-based hiring?
Evidence-based hiring means knowing, requirement by requirement, what a hiring decision actually rests on: a verified document, a demonstrated task, a structured answer, or only the candidate's claim. It is not a new tool or a new test. The Signal Gap shows where that evidence is missing.
What are the five levels of hiring evidence?
The paper records evidence at five levels: verified, demonstrated, structured, claimed and not covered. For each requirement, the audit records the strongest level the process holds when the decision is made.
| Level | What it means | Example | What it adds |
|---|---|---|---|
| Verified | Checked against a document or a third party before the decision | A certificate is confirmed with the issuer before the offer | Confirms that a fact is true |
| Demonstrated | Observed or tested during the process | A supervised practical task on site | Shows the candidate can do the task |
| Structured | Asked of every candidate and recorded against criteria written in advance | The same shift-pattern question for everyone, rated against a written standard | Makes candidates comparable and the decision reviewable |
| Claimed | The candidate's own statement only, on the CV or in an unstructured conversation | "Three years on reach trucks." | Useful information, but untested |
| Not covered | Nothing collected before the decision | Commute to a 05:30 start was never discussed | Nothing. The risk appears after the start date |
The levels are not a perfect ranking. A certificate check and a practical test answer different questions. But every level above "claimed" gives the decision something more than the candidate's own word.
"Claimed" is also not an accusation. It does not mean the candidate is wrong or dishonest. It means the process did not test the statement before relying on it.
Why is the Signal Gap often widest in frontline hiring?
The paper gives three reasons why the Signal Gap tends to be widest in frontline and blue-collar roles.
- Many requirements are not on a CV. Commute, shift pattern and physical pace matter on the floor, and no CV format records them.
- Many applicants have little formal experience. The CV says less. Research on structured methods designed for inexperienced applicants is also thin: the researchers behind the main validity estimates say they cannot yet tell whether structured interviews reach similar validity for inexperienced candidates (Sackett and colleagues, 2023).
- Key checks often come last. Certificates are frequently checked after the offer, so the decision is made on the claim.
Volume adds a fourth pressure. With a fixed number of recruiter hours, more applications per vacancy means less reading time per application. What survives is whatever is fastest to spot: a job title, an employer name, a date range, a gap. Date ranges turn directly into years of experience.
Validity here is an estimated correlation between what a selection method says about candidates and their rated job performance, corrected for measurement error: 0 means no relationship, 1 a perfect one. On the revised 2022 estimates, structured interviews average 0.42, a moderate link to job performance, and the highest of the 25 methods reviewed. Unstructured interviews average 0.19. Years of job experience average 0.07 (Sackett and colleagues, 2022). These are averages from many studies, mostly outside the Netherlands, and they measure overall job performance, not retention. This does not mean experience is irrelevant. It means the number of years, taken alone, tells you little about how someone will perform in the next role.
A different way to look at hiring quality
Most hiring metrics look backwards. Time to hire, cost per hire, early leaving, attendance and supervisor ratings all tell you how decisions turned out, weeks or months later. They are essential, but they arrive late, and they rarely tell you why a hire did not work out.
The Signal Gap looks at the decision itself, at the moment it was made. It asks what the process knew about each requirement when someone said yes.
The two views work together:
- Outcome measures show whether your process works. A rise in first-month leavers tells you something is wrong.
- The Signal Gap shows where it might be going wrong, and what to change before the next hire. If "accepts the real shift pattern" was never asked, you have a specific place to start.
That is why the paper lists "requirements by evidence level" as a measure alongside early leaving, attendance and supervisor ratings. One describes the decision. The others describe what came after.
Worked example: a warehouse operative
Illustration built for the paper, not client data.
Here is what one process held at the moment of decision:
| Requirement | Evidence level at decision | What happened | Possible fix |
|---|---|---|---|
| Reach-truck competence | Claimed | Stated on the CV and discussed briefly by phone | Demonstrated, where that is safe and proportionate |
| Valid reach-truck certificate | Claimed | Checked after the offer | Verified before the offer |
| Right to work | Claimed | Documents checked after the offer, before the first shift | See the note on Dutch ID rules below |
| Availability within the notice period | Claimed | Stated by phone; low risk | No change needed |
| Physical demands across a full shift | Not covered | Never discussed | Structured |
| Reliable arrival for a 05:30 start | Not covered | Never discussed | Structured |
| Match with the real shift pattern | Not covered | Never discussed | Structured |
Four of seven requirements are claimed. Three are not covered. None reaches verified, demonstrated or structured at the moment of decision.
The finding is about the process, not the people running it. It points to different kinds of fix:
- The certificate could be verified before the offer. Dutch law requires operators of forklifts and reach trucks to be properly trained (Arbobesluit, Article 7.17c). A certificate from a training provider is the usual proof, and many sites and clients require a current one. It is not a state licence.
- Right to work is different: Dutch rules limit what an employer may do with identity documents before hiring, so check with counsel what can happen before an offer.
- Physical demands, the 05:30 start and the shift pattern could be asked of every candidate against a written standard, making them structured. Ask about the job's demands and the candidate's experience of similar work, never about health or medical conditions.
- Reach-truck competence could be demonstrated, where that is safe and proportionate.
None of these fixes needs new technology to describe. Running them consistently at volume is a separate question.
Can the Signal Gap be scored?
The Signal Gap is auditable, not scored. There is no validated scale for it. A number would suggest more precision than the method has.
The audit produces two things: a simple record, and a count of requirements at each evidence level. That count describes one process for one role. It is not a benchmark, and it should not be compared across employers.
It also says nothing about individual candidates. A candidate whose experience is "claimed" is not a weaker candidate. The process simply holds weaker evidence about them. The fix sits with the process.
This distinction matters for technology too. A tool can help collect and structure evidence at the volume frontline hiring demands. It cannot take responsibility for the decision. Radius Hire's product shows three labels: Proven (broadly verified), Claimed and Missing (not covered).
How do you map your own Signal Gap?
You can map the gap for one role in about an hour, with a recruiter, a supervisor and the records from your last ten hires. In short:
- Write down what the role really requires, in a supervisor's words.
- For each requirement, record the evidence level your process reached at the moment of decision.
- Look for three patterns: weight without evidence (important but only claimed), evidence without weight (collected but never judged against a standard), and requirement without signal (important but never asked).
Start with the role you hire most often, and bring the supervisor into the room. The full one-hour method, the ten questions to test your answers and a four-week plan are in How to Audit Your Hiring Process for One Role in One Hour.
FAQ
What is the Signal Gap in hiring?
The Signal Gap, a term Radius Hire introduced in The Radius Papers 01 (2026), is the distance between what a hiring decision rests on and what predicts the outcome. You map it by recording, for each requirement of one role, what kind of evidence your process holds at the moment of decision.
What are the five levels of hiring evidence?
Verified, demonstrated, structured, claimed and not covered. Every level above claimed gives the decision something more than the candidate's own word.
Can the Signal Gap be scored or compared across employers?
No. There is no validated scale. The audit produces a record and a count of requirements at each evidence level for one role, and that count is not a benchmark between employers.
Is claimed evidence worthless?
No. A candidate's own account is useful information. It is simply untested at the moment the process relies on it.
Does closing the Signal Gap need technology?
No. Every fix can be done by hand. Technology helps when the same process has to run consistently at volume.
How is the Signal Gap different from quality of hire?
Quality of hire looks at outcomes after the hire. The Signal Gap looks at the evidence behind the decision at the moment it was made. Outcomes show whether the process works; the Signal Gap shows where to change it.
The Signal Gap series
Sources
- Radius Hire (2026). The Radius Papers 01: A New Standard for Frontline Hiring. Sections 1, 2, 5.3 and Appendix A.
- Sackett, P. R., Zhang, C., Berry, C. M., and Lievens, F. (2022). Revisiting meta-analytic estimates of validity in personnel selection. Journal of Applied Psychology, 107(11), 2040 to 2068. DOI 10.1037/apl0000994
- Sackett, P. R., Zhang, C., Berry, C. M., and Lievens, F. (2023). Revisiting the design of selection systems in light of new findings regarding the validity of widely used predictors. Industrial and Organizational Psychology, 16(3), 283 to 300. Open access. DOI 10.1017/iop.2023.24
- CBS (2026). De arbeidsmarkt in cijfers 2025, chapter 5, table 5.8. CBS labour cost chapter
- Arboportaal. Gebruik van arbeidsmiddelen (Arbobesluit, Article 7.17c). Arboportaal