No need to bother, tbh.
Your link focuses on
a) post-communism states ( Also: being in geographical europe isn't the same as being in the european union )
b) analyzes the situation prior to EU membership. ( Data is from 2001, the work was published in 2003 )
But at any rate, I've never claimed that you're incorrect about the differences how the official statistics are put up and that there are indeed motivations to appear better. Although I'd say the motivation to appear better would be to get into the EU, not to make the EU look better to the rest of the world.
Also you weren't exactly using Poland, Latvia and the latest bunch of joiners as an example but were targeting a founding member.
So we can refrain from going "Nuh-huh" at each other since it'll boil down to "It's not true because the EU fakes its statistics.".
With that I'm done with that topic derailment. Or take a look at crime rates (or
intentional homicide - I'm sure there's been a EU memo to fake these statistics, too).
As such - over and out.