The phrase "a primary weakness of" is correct and usable in written English.
It can be used when discussing a significant flaw or limitation in a person, system, or argument.
Example: "A primary weakness of the current strategy is its lack of adaptability to changing market conditions."
Alternatives: "a major flaw in" or "a key limitation of".
One additional caveat regarding the composite index: a primary weakness of this initial study is the temporal scale mismatch between our ecosystem service metrics and the beneficiary values derived from the survey.
"A primary weakness of this type of approach for domains with many skills or misconceptions is that the skills and misconceptions must be reasonably enumerated in order to provide feedback (Brown and VanLehn, 1980).
Due to the size of zebrafish embryos and the resolution that is required for phenotype analysis, the difficulties in capturing the entire embryo in 96- or 384-well plates reflect a primary weakness of this approach.
A primary weakness is the lack of exposure data to diisocyanates or other potential substances (e.g., unspecified contaminants in manufacturing process and cleaning solvents) that were likely present but not described.
For example, a primary weakness is the often-high level of nonspecific binding of nontarget proteins to the matrix, which confounds isolation of the true targets.
The primary weakness of Google's Daydream VR is still a lack of content, but the young platform got a bunch of new software today, including a sizeable list of new games.
The primary weakness of studies using conversion/stage change as an endpoint is that the rate of conversion, particularly from healthy to MCI or AD, may be low and variable across subjects and studies, depending on recruiting centers and entry criteria.
On the other hand, the primary weakness of the qualitative method lies in its subjective nature.
