Adjudicating

When adjudicating a chess match (not necessarily at the highest tournament level) how is this done? I understand points value and material worth and adjudicating on these terms appears straight forward. What about if you've been watching a match and it is glaringly evident that despite being in a winning position a person does not know how to finish. Do you award a draw based on this premise or do you still award them the win based on material advantage at a point in time?