FLAGSTAFF, Ariz. (AP) – A group of judges, prosecutors and tribal officials says not enough data exists to determine whether American Indian defendants are treated similarly for crimes under state and federal law.

The Tribal Issues Advisory Group released its findings after conducting the first review in more than a decade of the effect U.S. sentencing guidelines have on tribal communities.

The group is encouraging states to collect data on American Indians’ sentences.

It also has some suggestions for amending U.S. guidelines that ensure punishments for the same crime don’t vary widely across federal courts.

Among them is clarification on when tribal court convictions can be considered in federal cases. Convictions in state courts automatically factor in.

The group will present its findings and recommendations to the U.S. Sentencing Commission next month.