(This is a guest post by Dr Kevin Denny of the School of Economics & Geary Institute, UCD).
The extension of free GP care to under 6’s has raised the issue of what the effect will be on GPs’ practices. Understandably they are concerned about the increased demand on a sector that appears to be under strain. I am not aware of any specific research for this age group (mea culpa if I have missed it).
There are several studies for the general populations (various convex combinations of Anne Nolan, Brian Nolan & David Madden). I heard a very interesting recent interview on TodayFM with a GP Ciara Kelly. In the course of this, she said that children with medical cards visit a doctor 6 times a year while those without visited twice. From this she inferred that the new scheme would triple the demand of those currently without free care.A GP that I was once on a radio panel with said something very similar. I don’t know the origins of these numbers. However the average difference between the two groups is not relevant here: you need to know the marginal effect. Children currently without medical cards are different from those with: on average they are, inter alia, healthier and wealthier.
Estimates from other countries are not informative. I searched in vain for a government document that discussed this. We now have very good data in the form of the Growing Up in Ireland study. Here I report some estimates of what the effect of the reform might be. I use the second wave of the infant cohort – the three year olds who should be reasonably representative of the 0-5 age range. As dependent variable I use the question on “Number of times seen or talked with a general practitioner in the last 12 months”. This is top-coded at 20 but there are very few in that category. The variable of interest is whether they are covered by a medical card. I combine GP-only and the full medical card for simplicity.
I have a long list of controls which covers the usual suspects. They include health of the child and mother, income, education and other demographics. I also have a variable that indicated whether their GP visits are covered by private health insurance. Changes to the controls do not make much difference.
There are numerous ways of estimating such models and I used three. For the cognoscenti these are poisson & neg-bin2 regressions and a finite mixture of poissons. The marginal effects are very similar as is often the case. Before we consider those, what is the average difference in the data? In the GUI the population weighted mean of doctor visits for children covered and not-covered by medical cards is: 3.13 and 2.18 respectively. This is very different from the 6 and 2 mentioned above, the source of which I don’t know.
The marginal effects for the different models vary between 0.632 and 0.713, less than the average difference (as you would expect) and a lot less than the difference of 4 mentioned above. For simplicity I will take 0.68 as a ballpark value. So giving free GP care for under 6’s should increase the number of GP visits per child by less than one per annum. We are assuming homogenous effects: you could generalize this to allow the effects differ in various ways. The marginal effect of having private insurance is about 0.34. Since these are probably the better-off of non-medical card holders, this suggests that 0.68 is on the high side i.e. the effect on the kids of the rich of free GP care is probably lower, if anything.
I also estimated the model using the child cohort (the 9 year olds) for whom the marginal effect is about 0.33 incidentally. Estimates for adults tend to be in the 1-2 visits per annum range. So what might this mean in practice? The maximum number of children who could be covered by the present reform is about 270,000. Multiply by 0.68 & this suggests an extra ~183,600 GP visits a year. There are around 2,500 GPs in Ireland so this is about 73.5 visits a year each. If they work on average 47 weeks a year this would mean about 1.56 extra visits a week from the under-6’s for a GP. It would be interesting to know how much of a GP’s time this is likely to require.
The mean is not the only parameter in town. For doctors whose patients are already covered there will be little or no difference. Doctors in more affluent areas will likely bear the brunt. Doubtless there are additional complications.
For example, not all GP’s will sign up. I am ignoring general equilibrium effects, such as any ensuing change in the number of GPs. Perhaps the main known unknown is the labour supply responses of GPs to a switch from a per-visit fee to a capitation grant which encourages them to take on patients but spend as little time as possible with them. Extrapolation is difficult, especially about the unknown.
I don’t mean to suggest that my estimates are best, I can’t explore every possibility in a blog post. I think they are credible though. Readers may have better knowledge of some of these parameters.
A file with the full results is available at http://tinyurl.com/p9cu8ax