(AP) — A national school-finance expert is echoing a concern raised by many Nebraska public schools: that state aid needs to be predictable.

Policy analyst Michael Griffith urged Nebraska lawmakers on Wednesday to look for ways to make it easier for schools to anticipate how much money they will receive each year.

Aid has fluctuated in recent years, leading to conflicts between small and larger districts. Many have increasingly relied on property taxes since the recession, but surging farmland values and rising enrollment in urban schools have caused more money to flow to larger districts.

Aid is distributed through a formula that seeks to fill the gap between what school districts need and their local resources.

Nebraska is expected to distribute nearly $1 billion each year between July 2013 and June 2015.