# Would a simple OLS regression work with this example?

First and foremost I would greatly appreciate any help you can provide me with.

I am writing my undergraduate thesis on the rise of populism in France.

The relationship I am trying to better understand is as follows: Can we explain the rise in popularity of the National Front (political party) between 2000 and 2014 through the rising number of immigrant populations immigrating to France?

The data I have so far are the average popularity ratings per year for the political party, and the change in immigrants in France?

• It will be extremely difficult to support your hypothesis in any way. You are claiming a causal relationship between two observed values (and correlation doesn't imply causation). I don't rule out that a convincing approach is possible. But also I don't think a simple OLS will do it. – ziggystar Oct 26 '14 at 18:11
• Short answer: No. To be valid, any sort of statistical analysis would require much more sophisticated approaches (e.g. the realm of causal inference) as well as more data (since you'd need to address the issue of possible confounding variables), etc. – Steve S Oct 26 '14 at 18:12
• When these comments were posted I was just writing my own answer. In principle ziggystar and Steve S are saying the same in a much more condensed fashion. My answer tries to offer a potential way around it but in general their points are very important. – Andy Oct 26 '14 at 18:24
• OLS assumes the data is IID. Points in time series are dependent on previous points, which can produce a trend over time. If two time series show an upward trend during the same period, they'll be correlated even if there's no causal connection between them. For example, global temperatures were rising during the same period, but we don't look to global warming to explain the National Front's popularity. Tyler Vigen has great examples of time series producing spurious correlations. – Lizzie Silver Oct 27 '14 at 19:53