# Microgram: calculate-compute-prr

`station__algovigilance__microgram-calculate-compute-prr` · native (always callable) · domain `algovigilance` · pv-relevance `pv-core`

Compute Proportional Reporting Ratio (PRR) for a drug-event pair from a 2x2 contingency table. PRR > 2 with chi-squared > 4 and N >= 3 indicates a signal.

## Agent metadata

- `idempotent`: true
- `read_only`: true
- `expected_latency_ms`: unknown (not yet contract-tested)
- `cost_tokens_estimate`: unknown

## Input schema

- `a` *number* (required) — Reports of target drug WITH target event
- `b` *number* (required) — Reports of target drug WITHOUT target event
- `c` *number* (required) — Reports of other drugs WITH target event
- `d` *number* (required) — Reports of other drugs WITHOUT target event

## Example call

```json
POST /api/mcp
Content-Type: application/json

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "station__algovigilance__microgram-calculate-compute-prr",
    "arguments": {
      "a": 0,
      "b": 0,
      "c": 0,
      "d": 0
    }
  }
}
```

## Related

- [/tools](/tools) — all 7718 tools
- [/tools/algovigilance__microgram-calculate-compute-prr](/tools/algovigilance__microgram-calculate-compute-prr) — HTML page
- [/tools/algovigilance__microgram-calculate-compute-prr/json](/tools/algovigilance__microgram-calculate-compute-prr/json) — JSON form (agent-friendly)
- [/api/mcp](/api/mcp) — endpoint
- [/AGENTS.md](/AGENTS.md) — agent guide