text: The report was commissioned by Stormont's Department for Social Development (DSD) and the Department of the Environment (DoE).
  DSD had proposed an "affordable housing contribution" would apply to all developments of five homes or more.
  Similar schemes operate in the rest of the UK and the Republic of Ireland.
  The departments commissioned the research from Heriot Watt University and Three Dragons Consultancy.
  It concluded that introducing a scheme "with a single percentage of affordable housing across Northern Ireland will not work given current market conditions".
  It added that a scheme could be considered for greater Belfast but that "timing, percentage target and form of provision is best left to local decision makers".
  That suggests that it would be decision for councils on whether to implement a scheme.
  Social Development Minister Lord Morrow said: "This research report will make a valuable contribution to our evidence base on this issue.
  "My department, along with the Department of the Environment, will now reflect on the findings and recommendations detailed in the report."
target: A scheme to compel private developers to contribute towards building social housing is "not realistic" for most of Northern Ireland, a report has found.