Learning ObjectivesTo describe the major sources of health data on U.S. and international populationsTo describe the issues involved in appropriately interpreting these dataTo know how to address a research question using publicly available public health data on the InternetTo discuss criteria for assessing the quality and utility of epidemiologic dataTo discuss the uses, strengths, and weaknesses of various epidemiologic data sourcesTo know the differences among an outbreak, an epidemic, and a clusterTo define epidemic, endemic,and pandemicTo know the 10 primary steps in an outbreak investigation and the order in which they are usually performedTo know what a case definition is and why it is important in an outbreakTo be able to define, graphically depict, and interpret an epidemic curveTo define and be able to recognize a point source, common source, and propagated outbreakSamuel Johnson: developed the first English dictionary, was quoted as saying, "Knowledge is of two kinds-- we know a subject ourselves, or we know where we can find information on it." why do we like to use publicly available data sets? it has good documentation. And it can be done in a very timely fashion. We can also calculate rates based upon publicly available data. And this is a very important aspect of using these data.issues involved in interpreting rates and trends as they consist of comparing populations to one another based upon existing rates, real reasons why rates differ between populations is due to:difference in behaviors, difference in genetics, differences in environment, nutrition, and other risk factors which account for true differences in populations and why the rates of disease may differ. second category are based upon artifact: things in terms of data collection, data accuracy, how completely cases are identified in the population, improved technology, access to health care, and changes in coding, for example. Also things like diagnostic, and accuracies between populations, new technology. So new screening tests access to health care plays an important role in differences in mortalityhow more completely countries or populations ascertain or account the number of cases in the population. coding change can affect certain causes of mortality or certain disease categories, simply because the coding rules have changed for those classifications. since rates are comprised of both the numerator, which we've been talking about up until now, but also the population.
So these are reasons that are not true biological reasons, but are due to artifacts of data collection and so forth. World Health Organization assessment of how completely mortality is registered in the various WHO regions and WHO countries.