The availability of a comparator group may also allow the use of crossover related methods [ 33].
The specific design of this survey varied from country to country due to the limited availability of validated comparator instruments and local circumstances.
An additional strength of the study was the availability of a matched comparator group of obese patients who did not undergo surgical weight loss intervention.
These trials represent an important challenge since RV vaccines have to be introduced in many different settings, placebo-controlled studies are unethical due to the availability of licensed vaccines, and comparator assessments for new vaccines with clinical endpoints are very large, complex, and expensive to conduct.
PASS methodology is influenced by the background incidence of the outcome of interest, vaccine uptake, availability and quality of data sources, identification of the at-risk population and of suitable comparators, availability of validated case definitions, and the frequent need for case ascertainment in large databases.
Therefore, inclusion/exclusion criteria are set out to the least limitations that are necessary to perform the study meaningfully, i.e. availability of the results of the comparator 'renal allograft biopsy'.
43 In one study comparing two gonadotropins, probabilities of subsequent frozen cycle, based on expert opinion, were different for the two comparators, but availability of embryos for cryopreservation was not considered.
The output of comparator is the desired PWM signal.
In contrast, the perturbation score we applied in the present study is independent of comparator data.
The first part is a modulator consisted of comparator and triangular wave generator.
