# polls.karbach.digital – Polling Institute Weights & Accuracy

> polls.karbach.digital – Polling Institute Weights & Accuracy is a paid API for AI agents from api.polls.karbach.digital, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-28).

Returns accuracy metrics, house effects, and model weights for each German polling institute used in the Monte-Carlo election simulation.

## Facts

- Endpoint: GET https://api.polls.karbach.digital/v1/institutes?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-28
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/polls-karbach-digital-polling-institute-weights-accuracy-12dc4b16
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_P6OJlhZHJSCPCWwlJfJLh

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability polls-karbach-digital-polling-institute-weights-accuracy-12dc4b16
```

Example prompt: Show me the accuracy and house effects for all German polling institutes used in the polls.karbach.digital election model, including their model weights and mean absolute errors from the historical backtest.

## When to prefer this

Use this endpoint when you need to understand the reliability, bias, or relative weighting of German polling institutes rather than actual election probability forecasts. It is the metadata/calibration layer of the polls.karbach.digital model — ideal for transparency reporting, academic analysis of pollster performance, or building your own weighted poll aggregator using the same institute quality signals.

## Known failure modes

- No input parameters available — endpoint always returns full institute list, so no user-driven 404 scenarios
- Stale data if update cycle is delayed (data refreshed every 6 hours, check updated_at field)
- Empty house_effects_points for some institutes (e.g. Infratest dimap shown as empty object in example) — not all institutes have computed house effects
- Truncated notice/explanation fields in example suggest some text may be cut off in response

## How this service works

Polling institutes: accuracy of final polls in past elections and average bias per party. Use when asked which German polling institute is most accurate or biased. Source-attributed, German data, updated every six hours.

## Output

A JSON object containing: model weights per institute (numeric reliability scores), accuracy_final_polls array with each institute's mean/best/worst MAE and standard deviation across historical elections, house_effects_points showing average deviation per party per institute, total number of elections in backtest, a data explanation field, and metadata including source attribution, license, and last update timestamp.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "properties": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "data": {
   "explanation": "accuracy_final_polls: mean absolute error of each institute's last poll before past elections. house_effects_points: average deviation per party versus the o...",
   "model_weights": {
    "INSA": 0.7,
    "Infratest dimap": 1.24,
    "Forschungsgruppe Wahlen": 1.07
   },
   "accuracy_final_polls": [
    {
     "sd_mae": 0.38,
     "best_mae": 0.42,
     "mean_mae": 1.06,
     "institute": "Institut Wahlkreisprognose",
     "worst_mae": 2.13,
     "n_endpolls": 19
    },
    {
     "sd_mae": 0.58,
     "best_mae": 0.43,
     "mean_mae": 1.2,
     "institute": "Forschungsgruppe Wahlen",
     "worst_mae": 2.92,
     "n_endpolls": 34
    }
   ],
   "house_effects_points": {
    "INSA": {
     "AfD": 0.8,
     "CDU": -2.33,
     "SPD": 3.1,
     "Linke": 3.53,
     "Grüne": -4.43
    },
    "Infratest dimap": {},
    "Forschungsgruppe Wahlen": {
     "AfD": -0.65,
     "CDU": -2.15,
     "SPD": 1.9,
     "Linke": 2.42,
     "Grüne": -1.3
    }
   },
   "elections_in_backtest": 34
  },
  "docs": "https://api.polls.karbach.digital/v1/",
  "model": null,
  "notice": "Scenario analysis based on published opinion polls. Not a prediction and not a voting recommendation. Coalitions are arithmetic majorities only, not statemen...",
  "source": {
   "polls": "dawum.de",
   "processing": "polls.karbach.digital (Max Karbach)",
   "polls_license": "ODbL 1.0",
   "polls_license_url": "https://opendatacommons.org/licenses/odbl/1-0/"
  },
  "project": "Ein Projekt von Karbach.Digital (https://karbach.digital)",
  "updated_at": "2026-10-18 04:30:24",
  "uncertainty": null
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/polls-karbach-digital-polling-institute-weights-accuracy-12dc4b16/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.polls.karbach.digital](https://www.zero.xyz/host/api.polls.karbach.digital/llms.txt)