Mae’r dadansoddiad o gyfraniadau yn ddull gwerthuso sy'n seiliedig ar theori, sy'n briodol i adolygu rhaglenni gwaith cymhleth aml-lefel lle nad yw priodoleddau achosol uniongyrchol yn bosibl[1]. Mae'r dull hwn yn briodol ar gyfer gwerthuso effaith isafbris gan nad isafbris uned fydd yr unig ffactor a allai effeithio ar lefelau yfed alcohol a niwed sy'n gysylltiedig ag alcohol.
The contribution analysis is a theory-based evaluation method, appropriate to the review of complex, multi-level programmes of work where direct causal attributions are not possible[1].  This approach is appropriate for evaluating the impact of minimum pricing as an MUP will not be the only factor which may impact on alcohol consumption and alcohol-related harm.