# Pearson correlation coefficient - is correlation estimator acceptable?

As far as I know when it comes to theory, we use Pearson correlation when we want to check the correlation between two variables, which are both continuous or discrete. For a mixed case it's not so easy to use it to compute correlation coefficient. On the other hand, we have Pearson correlation estimators, where we can calculate mixed case without any problems (based on samples). Does the Pearson correlation coefficient give deceptive results in this case ?

• Pearson coefficient is fine for binary values. I think it still works if the categories are ordered right on the same scale. Commented Feb 23, 2020 at 20:31
• @keiv.fly I'm not talking about categorical variable, but about numerical, discrete variable. Commented Feb 23, 2020 at 20:38
• Wiki explains case mix as cohorts which are essentially categories. If you meant something else than categories you should explain what you mean by case mix. Commented Feb 23, 2020 at 20:48
• I meant that we had one continuous variable (e.g with normal distribution) and one discrete variable (e.g with Poisson distribution). Commented Feb 23, 2020 at 20:56
• Pearson correlation estimators: what is the formula or procedure to calculate the estimate? Commented Apr 4, 2020 at 16:06