The research of Maarten Vink, Floris Peters, and Hans Schmeets shows that a longer period before naturalisation decreases the probability that acquiring citizenship will positively affect the labour market prospects of immigrants. The Deputy Minister of Security and Justice Klaas Dijkhoff was asked to respond to these findings.
After the Social Democrats (PvdA) withdrew their support for the bill and also the Senior Citizens party (50PLUS) voted against there was no longer a parliamentary majority to support the proposal and the bill was rejected.
The studies (in Dutch) co-authored by Maarten Vink, Floris Peters, and Hans Schmeets be downloaded here and here.
Maarten Vink wrote a blog (in Dutch) about the parliamentary debate on the extension of the residence requirement for naturalisation.
More information about the proposed bill (in Dutch) can be found on the website of the Dutch Senate.