“…We define the regressors as follows: Here, TB i , k denotes the k ‐th break location for the i ‐th country, with k = {1, … , m i }, and m i ≥ 1. Because real per capita GDP in each African country was less than real per capita GDP in the USA in 1969, according to Carrion‐i‐Silvestre and German‐Soto (:318), there is evidence of a catching‐up process if the coefficients of the DU and DT parameters in each regime are significant at least at the 10% level of significance and have opposite signs, i.e. θ k < 0 and ρ k > 0, or θ k > 0 and ρ k < 0.…”