Even though the reported studies provide further insight in the association between living area and physical fitness, their added scientific value is limited because findings from cross-sectional studies do not allow the identification of cause-and-effect relationships.
The results presented here are subject to the limitations inherent to observational studies and, thereby, do not allow independent evaluation of cause-and-effect relationships.
This book proves that just as profound an affinity exists between history and the study of causes and effects—and water, which are at once both intricate and implacable.
No taking seriously of climate change if it conflicts with religious belief, and no study of cause and effect when believing has become a scary subtitute for the seeing of information.
Thus, this is a study of association and is not a study of cause and effect.
However, such misclassification, in epidemiologic studies of cause and effect, tends to be nondifferential and bias the results toward observing no effect (Checkoway and Eisen 2005).
Cross-sectional design did not allow us to study the cause-and-effect relationship of psychological morbidity with stress and coping strategies.
First, the cross-sectional nature of the study prevents assertion of cause and effect.
The observational nature of this study, however, precludes assessment of cause and effect, and further functional studies are required to elucidate the mechanisms underlying the links between amino acids and the risk of insulin resistance and overt diabetes.
Despite the consistency of the results, the observational nature of these cohort studies precludes an assessment of cause and effect because reverse causality or residual confounding cannot be excluded.
Limitations of the study include the fact that a cross-sectional study design involves the measurement of cause and effect at the same time, introducing the problem of temporal ambiguity in establishing causal relationships, and a reporting bias related to the presence of the researcher, conditioned by the hypothetical relationship between the interviewers and paramedical staff.
