You keep changing. First it was those who gave up should be included, now it's all marginally attached.Don´t distract.Then look at the U-4. The U-3 measures actual availability, not potential.
Why don´t you read the article? It is tampering:But it's not just school kids...what about the non-discouraged marginally attached (the U-5). They are also potential.
"“Marginally attached” describes individuals not currently in the labor force who wanted and were available for work. The official unemployment numbers exclude them, because they did not look for work in the 4 weeks preceding the unemployment survey. In July, this marginally attached group accounted for 2.2 million people."
And how on earth is sticking with a set definition "tampering?" Tampering means to change, to alter, to interfere. Having set categories and sticking with them is not tampering.
And as for your country tampering...I'll assume Germany based on the language in your profile. Germany has two main measures of unemployment. The Federal Employment Agency (Die Bundesagentur für Arbeit) only counts registered unemployed, while the Federal Statistical Office (Das Statistische Bundesamt) uses the ILO definitions and a labor force survey as compliance with Eurostat requirements. There is heavy oversight on all labor market surveys by the EU, so I'm not sure how you think there's tampering.
But the bottom line is this: If a person is not trying to work, he will not get a job. So to look and see that X number of people did not look for work and did not get hired tells us nothing. (In countries like Germany and France where the Employment Agency looks and finds work for the unemployed, being registered unemployed counts as job search).
What we want to know is how many people failed to get hired who could be working.