Are private health insurance subscribers unsatisfied with the Spanish National Health System?

The percentage of population having supplementary private health insurance (PHI) is related to the perceived quality of the National Health System (NHS). In turn, PHI purchase decisions influence the NHS quality given that the number of PHI subscribers determines NHS quality indicators related to congestion. On the other hand, being satisfied with the NHS includes an assessment of the NHS as a whole that goes beyond the mere perception of its quality. This paper estimates the probabilities of purchasing PHI and of being satisfied with the NHS as two simultaneous processes taking into account that NHS quality may influence but also be influenced by these two outcomes. We use data from a Spanish representative survey released in 2002. Following this empirical strategy we find that: (1) the likelihood of having PHI and being satisfied with the NHS is negatively and simultaneously associated; and, (2) naïve estimation models may be underestimating the impact of the NHS perceived quality on the likelihood of purchasing PHI.