Compute pairwise return correlation between backtests to measure how similarly strategies behave over time.

High correlation (>0.7) means strategies move together — poor diversification. Low or negative correlation means genuine diversification. Use after running multiple strategy variants to check whether they are real diversifiers or just correlated bets.

Args

• backtest_ids — 2-10 backtest IDs to compare.
• method — pearson (linear) or spearman (rank).

correlate_strategies([id1, id2], method="pearson")

Returns pairwise correlations plus a diversification assessment. Errors if fewer than 2 or more than 10 IDs, any backtest is missing, or equity curves are too short.