A Monte Carlo simulation was used to ascertain the degree of inflation that can occur in regression estimates when samples contain randomly occurring instances of a pattern among correlations called cooperative suppression. Ten thousand samples of scores on three variables were randomly drawn from a population in which the correlations among the variables were prespecified such that cooperative suppression did not exist. Cooperative suppression occurred in nearly 48% of the samples but the incidence of regression coefficients that were grossly discrepant from the population parameters was rare. The implications for multiple linear regression and a method of causal investigation called path analysis are discussed. (Author/CTM)