Nonlinear trend–reversion analysis for earlier centuries
Develop statistically significant nonlinear regression analyses of monthly financial data prior to 1871 to determine how the relationship between future returns and trend strength (including linear and cubic effects) evolved in earlier centuries.
References
Unfortunately, our data set is too limited to yield statistically significant nonlinear regression results for earlier centuries.
— Trends and Reversion in Financial Markets on Time Scales from Minutes to Decades
(2501.16772 - Safari et al., 28 Jan 2025) in Section 4.3 (Refinements and Extension to Medieval Times)