How come we can often see different data on the gender pay gap in case of the very same countries?

Reasons: differences in the method of calculation

In module 2 we could learn that we could reach different results of the gender pay gap depending on the method of calculation: whether the gender pay gap is calculated as the percentage of men's or women's wages and whether our calculation is based on the average wage or the median wage. We decided to calculate  the difference in accordance with the EU employment guideline between men's and women's average hourly wages as the percentage of men's hourly wage.