As the title of this article suggests, this is a descriptive piece (Polit & Beck, 2017). Following a brief description of high blood pressure, the numerical pressures at which the three stages of hypertension are diagnosed are listed in a table. (National Heart, Lung, and Blood Institute, 2011). There is no experimental design to study because that was not the purpose of this work (NHLBI). In an article that is designed to communicate important health information to the general populace, this is absolutely the correct format. Including experimental data that would elucidate why specific systolic and diastolic pressures are considered unhealthy would be spurious and get in the way of communicating the important information. This is not to say that medical information must be presented in a manner that indicates condescension, but that the material should be easy to understand without specialized knowledge.
This webpage from the CDC answers the question, “What is the prevalence of a variety of injuries in the United States, separated by the severity of outcome?” (CDC, 2011). This is still a descriptive study, but there is an experimental design to discuss (Polit & Beck, 2017). This is a survey study, where a sample population was interviewed with survey items intended to answer the question above (CDC, 2011). Neither the main page nor the data tables provide high-level detail of the study, but there is an additional link on the data tables with that information (CDC, 2011). The results of the study were reported first for the entire population and then broken out by cohort (CDC, 2011). Information on reliability is given using the relative standard error method (CDC, 2011). There is no attempt to prove a cause and effect here. Although the data is broken out by cohort, there is no suggestion made as to why the results exist, only that they do. Overall, this study is of limited use except as a starting point to investigate specific research questions related to the statistics presented.
As the title suggests, this study is designed to correlate cesarean rates with low birth weight and mother and infant mortality; specifically to test the hypothesis that cesarean rates higher than 15% are related to increased infant and maternal mortality (Volpe, 2011). The work is a meta-analysis of data collected from a variety of sources (Volpe, 2011). Each source had a different methodology used in its collection, from surveys to data officially reported to government agencies (Volpe, 2011). The data is presented as scatter plot diagrams. Statistical methods and variables are clearly defined and explained, and in cases where they are not, they are referenced from other sources. Both quadratic and exponential models were used to find the best-fit regression for the data (Volpe, 2011).
The conclusion reached was that there was an exponential inverse correlation between mortality and cesarean deliveries (Volpe, 2011). Further, there was no correlation between low birth weights and infant and maternal mortality and a cesarean rate greater than 15% so the hypothesis was not supported by the data (Volpe, 2011). As the author notes, this is important because future best practice regarding the appropriate level of cesareans in a population might be determined incorrectly if a positive or negative correlation were assumed (Volpe, 2011). The author admits that there may be several confounding factors in the study and cautions that more research is required (Volpe, 2011). In general, the research methodology in this study seems well designed and the results interesting if not groundbreaking.
Centers for Disease Control and Protection (2011). Fast stats: All injuries. Retrieved from http://www.cdc.gov/nchs/fastats/injury.htm
National Heart, Lung, and Blood Institute (NHLBI). (2011). What is high blood pressure? Retrieved from http://www.nhlbi.nih.gov/health/health-topics/topics/hbp/
Polit, D. F. & Beck, C. T. (2017). Nursing research: Generating and assessing evidence for nursing practice (10th ed.). Philadelphia, PA: Wolters Kluwer.
Volpe, F. (2011). Correlation of Cesarean rates to maternal and infant mortality rates: An ecologic study of official international data. Revista Panamericana De Salud Pública, 29(5), 303–308.