1. A method comprising: receiving one or more first parameters and one or more second parameters for a comparison of a first multilevel bill of material and a second multilevel bill of material; comparing, by a computer processor, one or more internal items based on the one or more first parameters to determine differences between the one or more internal items in the first multilevel bill of material and the second multilevel bill of material; if an internal item matches in the first multilevel bill of material and the second multilevel bill of material, performing: comparing, by the computer processor, one or more associations for the matched internal item based on the one or more second parameters to determine differences between the one or more associations in the first multilevel bill of material and the second multilevel bill of material; generating a report showing a result of the comparing of the one or more internal items and the comparing of the one or more associations, wherein the report shows unmatched internal items and unmatched associations for matched first items; and outputting the report.