{"uid":"cap_P6OJlhZHJSCPCWwlJfJLh","slug":"polls-karbach-digital-polling-institute-weights-accuracy-12dc4b16","name":"polls.karbach.digital – Polling Institute Weights & Accuracy","description":"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.","url":"https://api.polls.karbach.digital/v1/institutes?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":{"type":"object","properties":{"properties":{"type":"string"}}},"responseSchema":{"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}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.02","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.02/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.02","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.02","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_8j0Ba-c0ATePvJd0dKCEt","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.02","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Returns accuracy metrics, house effects, and model weights for each German polling institute used in the Monte-Carlo election simulation.","exampleAgentPrompt":"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.","exampleUseCases":[{"title":"Assessing pollster bias by party","prompt":"Which German polling institutes show the biggest house effects toward the AfD or SPD, and by how many percentage points do they systematically over- or underestimate them on average?"},{"title":"Selecting the most reliable pollster","prompt":"I want to know which German polling institute has the lowest mean absolute error in its final pre-election polls — give me the ranked list with their MAE and how many elections they were tested on."},{"title":"Understanding election model calibration","prompt":"How does the polls.karbach.digital model weight different institutes like INSA, Infratest dimap, and Forschungsgruppe Wahlen, and what's the accuracy record behind those weights?"}],"resultDescription":"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.","failureModes":["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"],"whenToPreferThis":"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.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-28T12:37:01.691Z","isFirstParty":false,"canonicalSlug":"polls-karbach-digital-polling-institute-weights-accuracy-12dc4b16"}