"make an objective assessment" is a correct and usable phrase in written English.
You can use it whenever you need to describe the process of evaluating a situation or making a judgment based on facts and evidence rather than personal opinions or biases. Example: In order to make an informed decision, I must first make an objective assessment of the pros and cons of each option.
Linguists have attempted to make an objective assessment of the relative difficulty of languages by breaking them down into parts.
Newly-appointed to the job, he had to stand back and make an objective assessment of where the company had gone wrong.
"The overuse of narcotics is a huge problem, and when a patient presents, especially for dental pain, it's difficult to make an objective assessment," she said.
"We do not have enough distance to make an objective assessment," he said, "but in any case, I think it crucial that the Afghan highest leadership take more visible and obvious ownership for their army".
Others bought stocks on the bullish advice of Wall Street analysts, whose research reports may have been written more to win the investment-banking business of the corporations being analyzed than to make an objective assessment of the future prospects of its stock.
The more you look in the mirror, without which it is impossible to make an objective assessment of how you look, the more depressed you get, the less you care, the less you want to look in the mirror at all, until finally you simply give up dressing well as a bad job.
I made an objective assessment of my risk factors and decided to stick with my strategy, tweaking a few things here and there.
DAI was assessed to make an objective clinical assessment.
To make an objective and reproducible performance assessment, we have designed and implemented a framework to generate realistic DNA copy number profiles of cancer samples with known truth.
This makes any objective assessment by potential prescribers difficult, if not impossible.
My main academic point is that it's nearly impossible to deny that race matters in politics even when one claims they are making an objective political assessment (see "Obamacare" and "Tea Party" or even reviews of Obama's debate performance).
