> ## Documentation Index
> Fetch the complete documentation index at: https://docs.consensus.app/llms.txt
> Use this file to discover all available pages before exploring further.

# Find human-factors evidence for a design decision

> Pull the biomechanics, ergonomics, and usability research behind a product or workstation choice, before the decision gets defended after the fact.

## What you get

The published human-subjects evidence for a design decision: what has been measured, in whom, under what conditions, with what effect size — and where the evidence simply does not exist for your population.

## Who it's for

Product designers, human factors and ergonomics engineers, sports-science and footwear R\&D teams, and occupational health groups. Corporate science teams doing kinesiology and biomechanics research sit squarely here.

## Why it belongs to human-subjects rules

This is the corner of applied R\&D where the evidence is about people, so the filters that matter are the clinical ones: `human`, `controlled`, and `sample_size_min` do more for result quality here than any materials or engineering filter.

## How it works

<Steps>
  <Step title="State the decision as an outcome question">
    Not "what does the research say about midsole foam" but "does increased midsole stiffness reduce metabolic cost in recreational runners". Named population, named intervention, named measurable outcome.
  </Step>

  <Step title="Demand human, controlled evidence">
    Set `human=true`, `controlled=true`, and a realistic `sample_size_min`. Biomechanics studies are often very small; a threshold around 15 to 20 filters out the least informative work without emptying the result set.
  </Step>

  <Step title="Match the population to your users">
    Trained athletes are not recreational users. Young male university students are not the general population. This literature has a well-known sampling skew, so read the population column before the finding.
  </Step>

  <Step title="Separate lab measures from field outcomes">
    A change in a gait parameter on a treadmill is not a change in injury rate in the world. Track which you have — this is where most overclaiming in this field starts.
  </Step>

  <Step title="Search the null result">
    Run the negative phrasing. In biomechanics, small studies with positive findings publish more readily than small studies without.
  </Step>
</Steps>

## The API call

```bash theme={null}
curl -G "https://api.consensus.app/v1/search" \
  -H "x-api-key: $CONSENSUS_API_KEY" \
  --data-urlencode "query=midsole longitudinal bending stiffness running economy metabolic cost" \
  --data-urlencode "human=true" \
  --data-urlencode "controlled=true" \
  --data-urlencode "sample_size_min=15" \
  --data-urlencode "domain=psych,eng,med" \
  --data-urlencode "page_size=50"
```

`domain=psych,eng,med` covers most of this literature — human factors work is split across psychology, engineering, and sports medicine, and restricting to one loses a third of it.

## What to check before you trust it

* **Read the sample description on every study.** Population mismatch is the dominant failure mode in this literature, and it is rarely visible in the abstract's conclusion.
* **Check effect size, not significance.** A statistically significant 1% change in a lab measure may be irrelevant to a design decision.
* **Watch for surrogate outcomes.** Comfort ratings, gait parameters, and injury rates are three different claims, and only the last supports an injury-reduction statement.
* **Small samples dominate.** Treat any single study as provisional; look for replication before it drives a design commitment.

## Related

<CardGroup cols={2}>
  <Card title="Substantiate a product claim with published evidence" icon="clipboard-check" href="/use-cases/claim-substantiation">
    Turn the evidence into a claim you can defend publicly.
  </Card>

  <Card title="Grade a set of papers with your own evidence rubric" icon="scale-balanced" href="/use-cases/evidence-grading-rubric">
    Score the studies consistently before deciding.
  </Card>

  <Card title="Best practices" icon="shapes" href="/use-cases/best-practices">
    Filter ladder and the rest of the primitives.
  </Card>

  <Card title="All use cases" icon="grid-2" href="/use-cases">
    Browse the gallery by persona.
  </Card>
</CardGroup>