Contents

Data Analysis

Time & Forecasting

Reading data that moves over time, and saying what happens next without lying.

Data Analyst track

Junior

Write correct SQL, build trusted dashboards, ask good questions.

  • Naive ForecastPredicting 'same as last time' — the baseline every model must beat.
  • Run RateExtending today's pace to the full period — and why it usually overstates.
  • TrendThe long-run direction underneath the noise.

Mid-level

Own an analysis end to end, from vague question to recommendation.

Senior

Own experimentation and metrics design; call out bad numbers.

  • ARIMAA classical forecasting model combining autoregression, differencing and moving averages.
  • AutocorrelationHow much a series resembles its own past, at each lag.
  • Exponential SmoothingForecasting by weighting recent history more than old history.
  • Forecast AccuracyJudging forecasts on held-out data, against a baseline.
  • Seasonal AdjustmentRemoving the calendar pattern so the underlying movement is visible.
  • StationarityWhen a series' statistical behaviour doesn't drift over time.

Staff

Shape how the organization measures and decides.

Nothing here yet.

Principal

Set measurement strategy across the company.

Nothing here yet.