How These Statistics Are Calculated
Net Run Rate is the difference between two run rates across a tournament. Take the total runs a team scored divided by the total overs it faced, then subtract the total runs it conceded divided by the total overs it bowled. Crucially, the ICC method aggregates across all matches rather than averaging each match's individual NRR — those two approaches give different answers, and only the aggregate one is official.
The all-out rule is the part everyone gets wrong. When a team is bowled out before using its full quota, NRR is calculated against the full allocation of overs, not the overs actually faced. Bowled out for 150 in 35 of 50 overs, the calculation uses 50. This is why being dismissed cheaply is doubly punishing — you lose the match and take a heavier NRR hit than the scoreline suggests. It is also why teams chasing a small target sometimes bat with apparently reckless urgency: the margin of overs remaining feeds directly into a tiebreaker that may decide qualification weeks later.
ERA normalises earned runs to a nine-inning game. The formula is (earned runs ÷ innings pitched) × 9, which puts every pitcher on the same scale regardless of workload — a reliever throwing 40 innings and a starter throwing 200 become directly comparable.
"Earned" is doing heavy lifting, and innings are counted in thirds. Runs that score due to fielding errors are unearned and excluded, on the principle that ERA should measure the pitcher rather than the defence behind him — a distinction that requires official scorer judgement and is the main reason ERA is not purely objective. Innings pitched are recorded in thirds, one per out, which is why box scores show figures like 6.2 innings meaning six and two-thirds. Treating that 6.2 as a decimal is the single most common ERA calculation error, and it produces a wrong answer that looks entirely plausible.