Hi, my name is Emily Gurley, and I'm on faculty at the Department of Epidemiology at the Johns Hopkins Bloomberg School of Public Health. Today, we're going to talk about surveillance system attributes and assessing performance of surveillance systems. By the end of this lecture, I hope you'll be able to list the nine surveillance attributes as described by the US CDC, and give an example of how each of these attributes applies to a surveillance system. Finally, you should also be able to compare and contrast surveillance systems using these characteristics or attributes. There are a number of readings that we recommend for this lecture, if you want to get as much out of it as possible. Two are descriptions of surveillance standards. One is the World Health Organization Surveillance Standards Manual, and that describes the number of defining characteristics of surveillance systems and characteristics that you can use to describe surveillance systems and judge how well they're performing. Now, the US CDC has another set of guidelines. They cover similar concepts, but are a bit more defined, and we'll be using those throughout this lecture. You should also read through Dr. Satter and colleagues paper on hospital-based surveillance for rotavirus gastroenteritis in Bangladesh, we're going to be using that as a case example in this lecture, as well as CDC's Public Health Surveillance for Cancer. The links for all of these documents are on the lecture page. Now, let's think about attributes of surveillance systems. You may wonder if a surveillance system is good or not. And really the question is, whether or not it's good? But isn't good for what? No surveillance system is perfect, and we have consider the surveillance objective to know whether or not a surveillance system is useful. So, there's not only one way to answer the question about whether or not a surveillance system is good. But it's useful to consider the various aspects or attributes of a surveillance system to determine how well it functions. One set of guidelines you can use to think about how well surveillance functions is the World Health Organization Surveillance Standards. It considers a number of elements related to case definitions and collection of data. So, they recommend that case definitions be clear, appropriate for the objectives of the surveillance, and consistent. Consistency is important because that will allow you to compare trends of your own data over time, and also to compare data from across surveillance systems. The WHO standards also include some criteria about reporting mechanisms. So, the reporting mechanisms for surveillance system should also be clear, efficient, and relevant. Meaning that the people who ultimately are going to make decisions based on the data are included in the reporting mechanism and the reporting chain. The standards also address analysis of data. And basic just that the analysis should be appropriate or the data type, and also useful for decision-making. These standards also address the infrastructure of the surveillance itself. And they talk about things such as personnel. So, the personnel should be able to understand and support the system, they should value it, and they should receive adequate training and supervision so that they can carry out their responsibilities within the surveillance system well. Finally, they recommend that you think about whether or not the surveillance system receives feedback from the various stakeholders, and whether or not that feedback is appropriate and motivating for those participating in the surveillance. So, these surveillance standards provide a rubric for thinking about surveillance, and all of its various components. Another way to think about surveillance characteristics are the nine attributes suggested by the US Centers for Disease Control and Prevention. Now, the US CDC is a public health agency for the United States. But these surveillance attributes are used globally as a way to assess surveillance systems and their performance. They're used in global training programs such as the FETP or Field Epidemiology Training Program which operates in many countries around the world. So, although they originate from the CDC, they really are a global resource. The nine attributes includes simplicity, flexibility, data quality, acceptability, sensitivity, predictive value positive, representativeness, timeliness, and stability. We're going to spend more time going through each of these concepts, and giving you examples of what they look like within a particular surveillance system.
