I'm guessing maybe I'm not understanding what type of blood donation this data set is for (unless it's platelet donation) because I'm wondering how some of the donors were able to donate so often. My understanding is that most organizations won't let you donate more than once every 8 weeks, and for some other organizations it's every 12 weeks.
For example in the training data set:
There are some cases like ID 474 (11 times in 11 months), ID 497 (8 times in 12 months) which seem too often. Then there are a lot of cases like 391, 471, and 377 which are listed as having donated twice but it says first donation and last donation are both 2 months ago. Then there is ID 313 who donate 5 times but first and last donations were both 14 months ago.
I don't know much about donating blood but are these platelet donations or is it really possible to donate blood 5 times in one month?