The matching law, regardless of the version, is a mathematical model that accounts for an organism's response rate as a function of the reinforcer rate. McDowell (2013) investigated to which extent a combined version of the quantitative law of effect (Herrnstein, 1970) and the generalized matching law (Baum, 1974) accounts for a substantial amount of the variance through several data sets. Even if I agree with most points raised by McDowell, there are 2 important issues within his reanalysis. Two out of 6 studies relied on pooled-subject data that are inappropriate for an investigation of the matching law (Caron, 2013). Moreover, the combined equation was not systemically investigated through all data sets. The current study casts some doubt on the empirical status of modern matching equations and thus shows that they still deserve extensive attention.Keywords: choice, matching law, pooled data, within-subject varianceThe matching law is a quantitative model that describes the response allocation of an organism according to the relative reinforcer ratio (Herrnstein, 1961). The model has evolved into two equations: the quantitative law of effect proposed by Herrnstein (1970) and the generalized matching law proposed by Baum (1974). The quantitative law of effect conceptualizes the absolute response rate as a hyperbolic function of the absolute reinforcer rate, respectively, Bs and rs in Equation 1:Theoretically, the parameter k corresponds to absolute response rate, and r e corresponds to extraneous reinforcers. Herrnstein's (1970) conceptualization implies that the absolute quantity of behavior and extraneous reinforcers are constant within an experimental condition. Thus, the quantitative law of effect is more a theory than a purely descriptive equation such as the generalized matching law,where Bs and rs are the same as Equation 1. The generalized matching law conceptualizes response ratios and reinforcer ratios as a power function. The exponent a is referred to as sensitivity, and the coefficient b is referred to as bias. The power function is also known in its logarithmic form:Every parameter, a, b, r e , k, and the explained variance from each equation, are obtained via an ordinary least-squares regression where parameters are generally free to vary, even though fewer studies imposed constraints on the parameters. McDowell (2013) attempted to unify both equations into a single framework. He evaluated through extensive data sets to which extent the modern matching equations (Equations 6 -9 from the target article) can account for a substantial quantity of the variance and whether residuals appeared systematically correlated. However, McDowell did not systematically investigate Equation 6= from target article and numbered alike here. Moreover, McDowell used two conceptually inappropriate data sets out of six sets. Instead of analyzing the matching law from single-subject data, he conducted analyses on pooled-subject data. Therefore, his analyses violate a simple assumption of matching theory, that is, the mat...