As consumer is a countable noun, is consumer or consumers the right word in this sentence and why?
The final delivery service is one work aspect that is needed to be completed partially through consumer effort.
The final delivery service is one work aspect that is needed to be completed partially through consumers effort.
Best Answer
With some exceptions, nouns used as adjectives - to modify other nouns - are mostly singular. For example, 'customer service'. In your specific example, 'consumer effort' would be understood to be the effort made by consumers in general, and there is no need to pluralise it. Remember that 'consumer effort' doesn't necessarily mean more than one consumer, anyway.
There are other contexts where you could use the same words in a different way and this may not apply. For example, in UK schools, it is common to have a "parents association". It would seem unusual to say "parent" when most children have two parents, and could sound exlusionary. Likewise, in similar contexts, you could refer to "consumers' effort" if you wanted to emphasise that the effort was made by a specific, countable number of consumers, rather than just consumers in general.