Each regression model looks at age in 10 year intervals and its effects on non-attendance of a particular health service.

The OR for patients between 0-10 was 0.52; (3 year intervals used here)

The OR for patients between 11-49 was 0.66;

The OR for patients over 50 was 1.15.

How does one interpret these values?

Is it correct to say that each average increase in 3 years, there is a 48% reduced risk for non-attendance? Does this also suggest that younger patients have an increased risk for non-attendance?

I would appreciate any advice, I'm quite confused by this!

Anyone? :( ]]>

I have to do a diff-in-diff estimator in order to evaluate the impact of the policy. The problem is that the policy is gradually implemented and in the first year of implementation, it affects 25% of the observations, then 50%,75% and 100% for the remaining years in the sample. The easiest thing to do is to remove the years in which the impact was gradual. However, I still have to somehow account for this gradual policy implementation.

I am wondering how can I do that? One thing that comes to mind is to guess, which observations were impacted by the policy in each of the years(so guess the 25% in year 1, and assign them the treatment and remove the other observations(that are not the control group) and do the same for each of the other years in which the impact was not 100%. Is that a legit thing to do and is there something else that I can do? (I do not observe which observations were impacted and have to guess based on very limited demographic information).

I would really appreciate some input. ]]>

I am completely new to linear regression so this may sound daft, but I'm wondering if its possible to test for a significant difference between the gradients of two linear regression lines, and if so how can I do this in SPSS?

Basically I'm comparing the number of foreign words learnt in a week by adults and children and have two linear regression lines which show that the number of words decreases very rapidly between the ages of 1-10 and much less rapidly between the ages of 20-55. I want to know how I can perform a statistical test to show this difference.

Thank you! ]]>