# Pearson correlation method using absolute values and relative values

I have a dataset with election results and crime rates per city. For each variable I have an absolute value (i.e. Total votes, Total crimes) and a relative value (i.e. Percentage shares of votes).

I want to calculate the correlation coefficient for some variables, but in the process I had a question about what value I need to use, if relative values or absolute values.

First I calculated z score for absolute values and then I calculated the correlation using excel. I also used pandas.DataFrame.corr() and pearsonr from scipy.stats.stats in python, in order to corroborate results.

For example, if I use absolute values I will get a positive correlation between candidate 1 and candidate 2.

x = df['Abs Cand 1'].tolist()
y = df['Abs Cand 2'].tolist()

print (pearsonr(x,y))
(0.95209664861187004, 0.0)


However, if I use relative ones I will get a negative correlation:

x = df['Rel Cand 1'].tolist()
y = df['Rel Cand 2'].tolist()

print (pearsonr(x,y))
(-0.99704737036262991, 0.0)


I was confused when I saw both results, and now I need some orientation to understand those differences.