Both Spearman and Pearson correlation coefficients quantify the strength (and direction) of the association between two variables. It's vital you remember that these two differ in the kind of association they are sensitive for:
Pearson correlation assesses linear relationships. It only works for continuous variables and is based on your data's raw values.
Spearman's correlation determines monotonic relationships, be they linear or not. It works for continuous or ordinal variables. It relies on the ranked values for each of these variables.
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