To the Editor.
—Dr Keeler and colleagues1 provide us with insight into patient behavior in choosing between fee-for-service (FFS) and MSA options. Using the RAND Health Insurance Experiment model, they demonstrate that the likelihood of market segmentation as a result of MSAs, with healthy consumers choosing health insurance programs that offer financial incentives, depends on the size of the MSA deductible: specifically, the larger the deductible, the larger the market segmentation. However, the effect of managed care (MC) on market segmentation, when compared with the MSA and FFS options, is not described.We have modified the Figure contained in their analysis to highlight consumer behavior in choosing among FFS, MSA, and MC options. In our Figure, the MSA and FFS lines are similar to those in Keeler et al. The less steep slope of the FFS line reflects the presence of a co-payment. The MC option is shown as a horizontal line,