STRASMORE/EXPLORE 2,170 QUERIES

Survivors-only average vs whole-cohort average, by starting year

Answered against 22 years of US equities and 12 years of US options data and published with the query that produced it. This result is stored as of 2026-08-22, from Survivorship Bias in Stock Data, Explained.

as of table 7×6read in context →
Survivors-only average vs whole-cohort average, by starting year — 7 rows by 6 columns, computed from US exchange, SIP and OPRA data.
cohort_yearcohort_sizegone_countsurvivors_only_pctfull_universe_pctgap_pct
20162728969209.9148.261.8
20172522819160.8117.343.4
20182669824121.488.732.6
20192646695138.1112.725.5
202026696398773.113.9
2021341695764.448.416
2022337869434.224.99.2
Rows × columns
7 × 6
Computed
Completeness
No missing values
Source
US exchange, SIP and OPRA market data
Licence
Strasmore terms · free, no signup
Formats
JSON · CSV · the SQL below

What each column holds

Column definitions for Survivors-only average vs whole-cohort average, by starting year, derived from the stored result.
ColumnTypeRangeNotes
cohort_year text 7 distinct values (2016, 2017, 2018…)
cohort_size number 2,522 to 3,416
gone_count number 639 to 969 count
survivors_only_pct number 34.2 to 209.9 percent
full_universe_pct number 24.9 to 148.2 percent
gap_pct number 9.2 to 61.8 percent

Computed from Strasmore's warehouse of US exchange, SIP and OPRA market data. Equity prices are delayed; options greeks and implied volatility are end-of-day. This result is stored, not recomputed on load — it is exactly the numbers that were returned on , and the query below is what returned them.

the exact SQL behind every number
WITH
    entry AS
    (
        SELECT
            ticker,
            toYear(date)                   AS cohort_start,
            argMin(toFloat64(close), date) AS entry_close
        FROM global_markets.stocks_daily_aggs
        WHERE toMonth(date) = 1
          AND date BETWEEN '2016-01-01' AND '2022-01-31'
          AND ticker NOT IN ('SPCX')
        GROUP BY ticker, cohort_start
        HAVING argMin(toFloat64(close), date) >= 5
           AND avg(volume) >= 250000
    ),
    outcome AS
    (
        SELECT
            ticker,
            argMax(toFloat64(close), date) AS final_close,
            max(date)                      AS last_bar
        FROM global_markets.stocks_daily_aggs
        WHERE date >= '2016-01-01'
        GROUP BY ticker
    )
SELECT
    toString(e.cohort_start)                                                             AS cohort_year,
    count()                                                                              AS cohort_size,
    countIf(o.last_bar < today() - 45)                                                   AS gone_count,
    round(100 * avgIf(o.final_close / e.entry_close - 1, o.last_bar >= today() - 45), 1) AS survivors_only_pct,
    round(100 * avg(o.final_close / e.entry_close - 1), 1)                               AS full_universe_pct,
    round(100 * (avgIf(o.final_close / e.entry_close - 1, o.last_bar >= today() - 45)
                 - avg(o.final_close / e.entry_close - 1)), 1)                           AS gap_pct
FROM entry AS e
INNER JOIN outcome AS o ON o.ticker = e.ticker
GROUP BY e.cohort_start
HAVING countIf(o.last_bar >= today() - 45) > 0
ORDER BY e.cohort_start

Run your own version of this

The same 22 years of US equities and 12 years of options data are queryable in SQL or plain English. A free account runs 100 queries a day and takes no card.

More from this analysisSurvivorship Bias in Stock Data, Explained
Symbols that printed a final daily bar, by year ranking 10×3 The January 2019 universe, grouped by what happened to each name ranking 9×4 Symbols relisted under a new issuer after a long silence ranking 5×4 Survivorship in the universe: names trading each year, share still listed in July 2026, and median return table 10×6 Same-bar decision vs a one-session lag: SPY, average session gain, 2016-2025 table 10×5 The hindsight ceiling: SPY buy and hold, the same year without its biggest up days, and perfect one-day foresight table 10×5 See all 2,170 queries →