Generally

The standard of review the Supreme Court applies in  appellate cases identifies the level of deference the Court must accord a  district court's decision.  Cole v.  Valley Ice Garden, L.L.C., 2005  MT 115, ¶ 3, 327 Mont. 99, 113 P.3d 275.   The Montana Supreme Court has clarified that:  "Basically, our cases fall into two  categories--those that apply a de novo standard of review, thus treating our  review of the trial court's decision as a legal question--and those that apply  an abuse of discretion standard of review, effectively treating the court's  decision as an evidentiary issue."  Johnson v.  Costco Wholesale, 2007 MT 43, ¶  15, 336 Mont. 105, 152 P.3d 727.  Where  an issue presented on appeal does not involve an exercise of discretion by the  district court, the appellate court's review of the district court's legal  conclusions is de novo, or plenary.  See Giambra v.  Kelsey, 2007 MT 158, ¶ 26, 338  Mont. 19, 162 P.3d 134.  An appellate  court reviews discretionary trial court rulings for an abuse of  discretion.  See Giambra, ¶ 28.  When a  district court judge is presented with, and resolves, conflicting evidence, the  Supreme Court reviews the district court's factual findings to determine  whether they are supported by substantial credible evidence and whether they are  clearly erroneous.  Cole,  ¶ 3.

In Montana, there are two levels on which appellate  review may occur.  A district court has  appellate jurisdiction "in cases arising in justices' courts and other courts  of limited jurisdiction in their respective districts" (this includes, for  instance, decisions of special masters).  Section 3-5-303,  MCA.  The Montana Supreme Court has  appellate jurisdiction over "all cases at law and in equity;" that is, it  reviews district court decisions when the district court either exercises its  original jurisdiction or acts in an appellate capacity.  See §  3-2-203, MCA.  The level of deference to which a district  court's determination on a given issue is entitled may vary depending on  whether the district court is acting as the fact-finder.