As with any research study, conclusions based on this investigation are limited by several weaknesses, imposed by our choice of study design and the assumptions we made.
This difference might be explained by the choice of study population or registration, as our data include all admissions, whereas the above studies included only admissions to medical units, where a larger share of AF patients might be expected than in an overall hospital setting.
This paper explores the implications of choice of study design by examining how the findings of several evaluation studies made in Norway depend on choices made with respect to:.
In this paper, we review genetic risk prediction studies from a methodologic perspective by focusing on factors in the choice of study design and population that may have impacted the observed predictive ability.
The lack of clear consistency across studies of NSAID use and prostate cancer risk may be explained by factors related to study design, including choice of study population, exposure definition and assessment, length of follow-up, prostate cancer detection, and confounding.
Problems include "boundary shrinkage," whereby estimates of risk are exaggerated by choice of areas/time periods/demographic strata for study, variable ascertainment or duplication of cases, denominator errors, and publication bias.
For hospital cases, we examined how inferences drawn from a case control study can differ by choice of hospital- vs. community-based controls.
Our work shows that a successful model is strongly controlled by choice of hydraulic conductivity (for simulations in this study, 70 m day−1 was optimal), the ratio of kariz hydraulic conductivity to aquifer conductivity (107 was optimal in this study), as well as the length of the kariz in contact with the water table.
