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Common mistake lookup

Search quantitative research mistakes

Use this lookup to map recurring research, data, and risk-review mistakes to concrete diagnostics. Treat each result as a starting point for improving assumptions, evidence quality, and review discipline.

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2 matching entries

Review methods →
DataData

Failed or delisted observations are missing

Typical symptoms

  • The sample only includes current winners
  • Older periods show suspiciously strong quality
  • Universe construction is not documented

Likely causes

  • Current constituents were applied backward
  • Unavailable or failed observations were removed
  • Data coverage limitations were not disclosed

Checks

  • Rebuild the universe as of each historical date
  • Count missing observations by period
  • Compare current-only and historical-universe results

Resolution path

  • Use historical membership where available
  • Disclose coverage gaps
  • Treat current-only analysis as limited exploratory evidence

Related terms: survivorship, universe, delisting, coverage

DataData

Analysis uses information that would not have been known

Typical symptoms

  • Historical results look unusually smooth
  • Signals depend on revised or future data
  • Performance falls apart when timestamps are shifted

Likely causes

  • Inputs were aligned to the wrong timestamp
  • Corporate actions or classifications were applied retroactively
  • Final-period values were used inside the period being tested

Checks

  • Audit each input's availability time
  • Shift features forward and backward to test sensitivity
  • Review whether labels were known at decision time

Resolution path

  • Use point-in-time datasets where possible
  • Lag inputs conservatively
  • Document any unavoidable timing approximation

Related terms: lookahead, timestamp, point-in-time, feature lag

Educational boundary

This lookup is for research troubleshooting and reproducibility. It is not financial, investment, trading, tax, or legal advice. Prefer conservative assumptions and independent review when evaluating any analytical result.

InQuantWeTrust publishes educational content for quantitative research and analytical methods. It does not provide personalized advice, trade recommendations, managed services, or guaranteed outcomes.