The study found that such cases accounted for more than a third of the Planning Inspectorate’s workload of large housing applications.
On average, schemes were delayed by 10 and a half months while the appeal took place.
David Graham, senior associate director at NLP, said: "The findings may give some reassurance to officers that in the vast majority of cases their recommendations to approve will be upheld as sound.
"However, the down side is that councils have to pick up the tab for the fees of advocates and, increasingly, external witnesses, employed to defend refusal reasons.
"The volume of these cases must also be a concern to the inspectorate, particularly given the predicted increase in appeals and government plans to speed up the system including the proposed 12-month planning guarantee."
NLP examined 28 appeals relating to large housing applications which were recommended for approval but turned down by councillors, and found 19 were successful.