# F1-conf-02 — Balanced-panel mean life expectancy, 2000–2022

# Question

Change in unweighted mean life expectancy at birth (WDI SP.DYN.LE00.IN) between 2000 and 2022 over the fixed set of countries with a recorded value in every year 2000–2022 (balanced panel). The 2022 mean over all available countries is reported only as a descriptive baseline.

# Data and exclusions

data/life_expectancy_panel.csv: 439 data rows (n_input_rows), 20 distinct iso3 codes (n_countries_total). Issues found (data_issues):

• TUR appears under two names ("Turkey", "Turkiye") from the two extractions, 23 duplicated (iso3, year) rows; values identical in all 23 pairs, so one row per country-year was kept and the name harmonised to "Turkiye".
• BGD, ETH, IND, NGA have rows only for 2011–2022 → excluded from the balanced set.
• CHE has an empty value for 2007 → treated as missing (no interpolation) → excluded.

Exclusion ledger (out/exclusions.csv): 439 → (year scope, 0 removed) 439 → (dedupe, −23) 416 → (countries lacking year rows, −48) 368 → (countries with an empty cell, −23) 345 = n_analysed. Balanced set: 15 countries (n_countries_balanced, balanced_countries: AUS, AUT, BEL, CAN, DEU, ESP, FRA, GBR, ITA, JPN, KOR, NLD, SWE, TUR, USA); 5 incomplete (n_countries_incomplete).

# Method

Simple unweighted mean of life expectancy across the 15 balanced countries in each year; change = 2022 mean − 2000 mean. Baseline = mean over all distinct iso3 with a recorded 2022 value (after deduplication, so TUR counts once). Deterministic; no randomness (random_seed = null). Results were cross-checked by an independent recomputation without pandas (see out/state/checks.md).

# Results

• Balanced mean 2000: 78.060 years (mean_2000_balanced).
• Balanced mean 2022: 81.553 years (mean_2022_balanced).
• Change 2000–2022: +3.493 years (change_2000_2022_balanced).
• Baseline, all 20 countries with a 2022 value: 78.692 years (mean_2022_all_available, n_countries_2022_all_available). It is about 2.9 years below the balanced 2022 mean because it includes the lower-life-expectancy countries (BGD, ETH, IND, NGA) left out of the balanced set; this shows why the baseline is not the estimand.
• Yearly balanced means are in balanced_yearly_means. They peak in 2019 (82.073) and dip in 2020 (81.320).

# Uncertainty

These are descriptive figures computed exactly for a fixed set of countries. There is no sampling design, so no sampling standard error or confidence interval is reported. The only uncertainty is in the source estimates themselves: WDI values are modelled and get revised between releases, and this file does not quantify that.

# Limitations and open issues

• The balanced set has 15 countries and is mostly high-income (TUR is the only middle-income member). It leaves out all four lower-income countries and Switzerland. So the change describes this group of countries, not the 20-country sample or the world.
• Switzerland is excluded only because of one empty cell (2007). This follows the rule as written (no interpolation).
• The means are unweighted, not weighted by population.
• The two TUR extractions agreed exactly, so the deduplication did not depend on which copy was kept. The README gives a SHA-256 for the raw API response, not for the CSV, so I could not check the CSV against it.
• Feasibility: complete.