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About speaker

Viktor Tisza

Diligent

Creator of the open-source election forecast engine Kronikas

Viktor Tisza has spent more than 15 years in data science, machine learning, and AI, leading research and engineering teams across international finance and technology. His path has included co-founding an AI startup that was later acquired.

Outside his day-to-day work, he founded SzázKilencvenKilenc, an independent, nonpartisan, data-driven election forecasting project for Hungary’s 199-seat parliament, inspired by Nate Silver’s FiveThirtyEight methodology.

At its core is Krónikás (www.kronikas.eu), a hierarchical Bayesian model he built to estimate pollster-specific house effects and track vote-share dynamics over time. It’s designed to be country-agnostic rather than Hungary-specific. Viktor applied it across three Hungarian election cycles in a polling environment where government-aligned and independent pollsters diverge sharply. He later made it open source, and now it is applied in multiple countries.

Talk details

Day 2 (10/1)

11:10 – 11:55
thu 1
11:10 – 11:55
Talk
Data

Your Data Has an Agenda: Forecasting Elections When the Polls Take Sides

Viktor Tisza
Viktor Tisza Creator of the open-source election forecast engine Kronikas at Diligent
Forecast

Every forecast is a bet on which data to trust, and that bet gets harder when the polls themselves become campaign weapons. This talk explains how a hierarchical Bayesian model forecasts elections: it tracks how opinion drifts, learns each pollster’s systematic bias, and turns conflicting surveys into probabilities with honest uncertainty. The case study is Hungary’s 2026 election, where SzazKilencvenKilenc (199), an independent poll aggregator, used it to forecast all 199 seats in parliament. Its engine, Kronikas, is now open source and already powering forecasts for elections internationally. We close with where polling is heading, and why the same approach works anywhere business data sources disagree.

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Data

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