I replicated momentum-strategy returns for different markets and want to show that I have done it "right". I got research data for comparison and want to calculate the correlation between this data and mine. Which correlation coefficient is appropriate for stock returns? Pearson and Spearman both give similar results but I want to be able to explain why I have taken the specific one. So far I know that the interpretation for Pearson would be somewhat like : "The difference from the series' mean correlates". But is this what I would need in the case of stock returns?
Second question would be: Do I have to compare logarithmic returns since they are normally distributed or can I take the normal returns for measuring correlation?