Decades of work has been dedicated to developing and testing models that characterize how people make inter-temporal choices. Although parameter estimates from these models are often interpreted as indices of latent components of the choice process, little work has been done to examine their reliability. This is problematic, because estimation error can bias conclusions that are drawn from these parameter estimates. We examine the reliability of inter-temporal choice model parameter estimates by conducting a parameter recovery analysis of 11 prominent models. We find that the reliability of parameter estimation varies considerably between models and the experimental designs upon which parameter estimates are based. We conclude that many parameter estimates reported in previous research are likely unreliable and provide recommendations on how to enhance reliability for those wishing to use inter-temporal choice models for measurement purposes.