The causes of segregation are complex and varied as we have discussed in our ACCEPT PLURALISM research reports. In some cases, school admission policies based on academic achievement have the effect of separating out Roma (underachieving) students into separate schools. In other cases, residential segregation is a primary determinant of school segregation, with the phenomenon of white flight exacerbating already segregationist tendencies at both residential and school levels. In still other cases, loose alliances of teachers, parents, and sometimes school administrators join forces with the academic interests of the children in mind to remove or segregate 'disruptive' Roma pupils from classrooms and schools. These and many other factors interact in ways that effectively keep Roma children segregated in schools across much of Europe. This does not mean that the problem of school segregation has been ignored on a policy level: far from it. Governments on both the left and right in the countries studied have often made desegregation efforts a priority, with numerous attempts to reverse the segregation trend. These efforts are mostly aimed at different forms of integration: getting and keeping Roma pupils in mixed classrooms and schools. The one thing these policies all share in common is that for the most part they have failed. In spite of their efforts (notable in some cases) the segregation problem persists; indeed, in some cases it has worsened, and policies aimed at desegregation have inadvertently contributed to increased segregation. Often, these policies lack the political clout necessary for their successful implementation.