The phrase "a reduction over time" is correct and usable in written English.
It can be used when discussing a gradual decrease in quantity, size, or intensity over a specified period.
Example: "The study showed a reduction over time in the levels of pollution in the river."
Alternatives: "a decrease over time" or "a decline over time".
"A reduction over time seems consistent with the international environment and with the government's declared efforts to reduce it.
Compression of mortality is a reduction over time in the variance of age at death.
Both variables present the same overall pattern, with a reduction over time, especially between 2006 and 2011.
Mortality improvement is a reduction over time in the age-specific death rates and a corresponding increase in the cumulative survival probabilities and age-specific residual life expectancies.
Compression of morbidity is a reduction over time in the total lifetime days of chronic disability, reflecting a balance between (1) morbidity incidence rates and (2) case-continuance rates, generated by case-fatality and case-recovery rates.
A reduction over time of the shares of administrative costs is not unexpected.
The proposals include a phased reduction over time, or an immediate and complete elimination of military seats in Parliament.
Conversely, newly created regions may also be unusually long; while this may not affect promoter function, we expect a length reduction over time, either due to a mutational bias towards deletions [ 6] or due to selection for genome compactness.
In a low-stakes assessment such as PISA, a systematic reduction over time in levels of engagement or effort in equivalent cross-sections of students who have otherwise equivalent levels of proficiency is likely to produce an increase in the proportion of skipped or inadequately attempted responses to test questions (see van Barneveld, Pharand, Ruberto and Haggarty, 2013, pp. 46-48).
After placebo administration, a consistent reduction over time in heart rate was observed during the night-time period (−15%, P=0.019).
For example, grassland and meadow patch density at small spatial scales (<200 m radius), which was found to be important for protected butterfly species, had a greater reduction over time in the managed watershed when compared to the abandoned watershed.
