The phrase "affects the proportion of" is correct and usable in written English.
You can use it when discussing how one variable influences the ratio or distribution of another variable in a specific context.
Example: "The new policy affects the proportion of employees who work remotely compared to those in the office."
Alternatives: "influences the ratio of" or "modifies the distribution of".
The firm's risk attitude towards climate change negatively affects the proportion of eco-efficiency technology in the portfolio.
The data show that freezing rate affects the proportion of spermatozoa that retain their fertilizing ability post-thawing.
Unemployment adversely affects the proportion of the total disposable income received by the low income households and tends to generates economic conditions that negatively affect life expectancy.
Equation 9 describes how the low temperature cut-off (L) affects the proportion of heating, measured in heating degree days (HDD), provided by heat pump.
Objectives: Quantify baby being with mother postpartum, what level of care is provided, if level of care affects the proportion of babies with their mothers and examine maternal outcome overall.
The timing of this transition affects the proportion of latewood within an annual ring as does the amount of growth that occurs during the period that latewood is being produced.
This study demonstrates that the location of the collected ash sample in relation to the overall distance from the vent affects the proportions of bubble populations (larger vs. smaller bubble modes) preserved as vesicle imprints on collected ash grain surfaces.
GC content not only affects the proportions of amino acids encoded by a genome, but also the sequence complexity of the encoded proteins.
Hence the choice of covariates that are included in the modelling affects the proportions of non-responders that are 'imputed' as smokers by the model.
Matching (particularly by age) also affects the proportions of participants placed into each category such that they are not representative of the target population.
This can occur for a gene that is alternatively spliced, but for which a polymorphism exists that affects the proportions of alternative isoforms produced.
