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Evergreen explanations of point-in-time data, backtest bias, and the mechanics behind the datasets in the catalog.

evergreen · updated 2026-09-22

Point-in-time market data: as-of dates, restatements, and adjustments

Point-in-time data records what was known on each date, not what is known now. How as-of dates, restatements and corporate-action adjustments change what a backtest sees.

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evergreen · updated 2026-09-22

Survivorship bias in backtesting: how current constituent lists hide failures

Survivorship bias makes a backtest trade only the companies that survived. Why a current constituent list hides failures, which way the error points, and what fixes it.

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evergreen · updated 2026-09-22

Look-ahead bias in quantitative trading: six mechanisms and their fixes

Look-ahead bias is information a backtest uses before it existed. Six ways it leaks in, the timing mistakes that survive data-quality checks, and how purging and embargo work.

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evergreen · updated 2026-09-22

Delisted stock historical data: why delisted names decide a backtest

Delisted stocks hold the worst returns a long-only backtest never sees. What a delisting record must contain, why ticker joins fail, and how halts and transfers differ.

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evergreen · updated 2026-09-22

Dollar bars vs time bars vs volume bars

Time bars sample on the clock, volume bars on shares traded, dollar bars on dollars traded. How each rule changes the number of bars and the shape of the returns.

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evergreen · updated 2026-09-22

An MCP server for quantitative research

The Model Context Protocol lets a language model call typed tools instead of reading pasted spreadsheets. What a quant research server should expose, and which hazards it closes.

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