Abstract
Background
Empirical research on the relationship between CSR disclosure and firm value in African financial markets shows methodological consistency and uses mostly fixed-effects regressions together with carefully chosen theoretical controls. Such an approach implies linearity and may suffer from variable selection bias, omitting important nonlinearities and thresholds.
Methods
This study employs feature importance rankings obtained through the Random Forest and Gradient Boosting machine learning algorithms combined with Shapley Additive Explanations for a balanced panel with 800 firm-years of data, consisting of 80 firms in South Africa, Nigeria, Kenya, and Ghana for the years 2015–2024. Results are compared against two-way fixed-effects regression coefficient estimates based on 83 predictors.
Results
There is considerable congruence between the results obtained via the three methods used in this paper with regard to the most important predictors: the first four places are taken by the CSR score, return on assets, institutional quality, and firm size. In turn, the fixed-effects approach fails to give proper weight to board independence, political risk, CEO duality, and environmental disclosure due to the presence of thresholds or nonlinearity. The SHAP algorithm reveals a threshold value of 40% for board independence, an interaction effect between CSR disclosure and firm size limited to the small-cap category, and an effect of CEO duality depending on institutional quality.
Conclusions
Machine learning feature importance rankings serve as valuable means of variable discovery that help improve specification of fixed-effects regressions. The suggested two-step procedure involves variable discovery through machine learning followed by causal inference with the use of fixed-effects regression. The proposed congruence framework is replicable to other CSR panels.
JEL Classification:
C55; G15; M14; O55