“…This evaluation research context presents two main problems. On the one hand, as a conceptual-theoretical framework, the Campbellian tradition presents a series of threats to validity that can affect four different kinds of validity ( Campbell, 1957 ; Campbell and Stanley, 1963 ; Cook and Campbell, 1979 ; Shadish et al, 2002 ): (a) statistical conclusion validity ( García-Pérez, 2012 ) can be affected by a low statistical power ( Tressoldi and Giofré, 2015 ) and a restricted range ( Vaci et al, 2014 ); (b) internal validity can be affected by selection, history, maturation, and regression; (c) construct validity can be affected by construct confounding, treatment-sensitive factorial structure, and inadequate explication of constructs; and (d) external validity can be affected by interaction of the causal relationship with units or outcomes. Although Campbell’s approach provides a conceptual framework for evaluating the main threats to four types of validity ( Shadish et al, 2002 ) and some guidelines (design features) to enhance validity were presented, there is not an empirical, systematic approach to check and control the influence of threats to validity on the treatment effect estimations in program evaluation practice (e.g., Stocké, 2007 ; Krause, 2009 ; Johnson et al, 2015 ).…”