Overall, the same amounts of mineral and organic soil were used in both treatments to prevent differences in nutrient content.
Plants in natural populations are highly variable, depending on the conditions in which they grow, so we used pot-grown experimental plants to ensure that, as far as possible, resources were controlled to prevent differences in plant growth and development between treatments and sites.
The risk of dying in the other treatment centres varied between the risks of centres B and C. To prevent differences in the socio-ethnicity status of patients interfering with the comparison with the model, the mortality rates in the three centres was then recalculated only for Dutch men that acquired HIV through sex with men (i.e. Dutch MSM) (n = 3946, 31% of the total dataset).
A second purpose of blinding is to prevent differences in other aspects of patient management introducing biases affecting the results.
This prevents differences in costs between groups due to an unequal number of OTs, physicians, managers and/or clients.
Restricted food intake was necessary to prevent differences in food consumption and hence differences in vitamin and mineral intake as observed earlier in FOS interventions [ 3].
To prevent differences in the timing of insulin dose administration from confounding the results, the IDeg flexible dosing arm in study 3668 was excluded from this meta-analysis.
It has also been suggested that gene flow between sexual and asexual functional parthenogens producing males may be sufficient to prevent differences in heterozygosity accumulating between reproductive modes.
The standardised period of 30 days was chosen to ensure a fair inter-hospital comparison and to prevent differences in length of stay from affecting the measurement.
We standardised male attractiveness (z-transformation) within trials to prevent differences in mean female responsiveness among trials from generating spurious correlations.
