But you can deviate from this optimal number if circumstances preclude that.
For example, you can deviate from this optimal number due to the type of role you are hiring. Perhaps you'd like more views for hiring a senior role because you'd like to involve all relevant stakeholders in the hiring decision. Or perhaps you'd like less reviews per answer if you are hiring a high volume role, because you want to have a good balance between crowdsourcing and the burden you add to your team.
You can adjust the number of reviews according to your needs when you allocate sift answers to review.