One thing that jumps at me in this study is the high risk of investigating two different populations with different characteristics. Foreign students are more likely to be high achievers (and high-achieving women), quantitative degrees are also in higher demand from foreigners and more likely to be in English. If you are Dutch you can pick whatever university&#x2F;field you want and they will admit you (exception is medicine); thus there is a higher chance of low-achievers (who drive the results) to be in that part of the sample. I am suspicious of results which are driven by the tail of the distribution and die out in time (when that tail drops out).