Low or high correlation?

What does it mean when Pearson correlation gives a value of 0.7-0.8, while spearman correlation gives a value from 0.3-0.4? Pearson reports high correlation while Spearman report weak. Should I conclude that the correlation is weak using spearman since the data seems skewed?


Fortran must die
There are various opinions about when you should and should not use these two. The one I was taught was that spearman was used for ordinal data and pearson for interval (pearson can not address non-linarity, spearman will work with non-linear data if it is monotonic in nature that is you have one rather than multiple directions for the curve).

I have not heard that logs work to eliminate outliers - they stabilize variance. There are robust methods to address outliers, but they are not simple (such as M estimators).


TS Contributor
Regardless the outlier(s), I would like to inspect the whole scatter of data points to have a broader idea of the correlation....


Fortran must die
One thing a scatterplot may catch is if there is non-linearity and if there is, is it monotonic or not. That will have a lot to do with what approach (pearson or spearman) you use.