In this section, we're going to talk about data for action. Public health surveillance data, is all about action. Why do we need data to act? Well, we're really going to be most efficient and effective in our actions to protect public health, if those actions are informed by data. So, let's think about that for a moment. So, in order to act, we need to know, what is the pathogen that's causing disease? What is the condition that's causing the most suffering in a population? Who's being affected by this condition that we're worried about? Where do those people live? Are they in the cities? Are in the in the towns? When are they being infected? Is there any particular time of year or is this an ongoing problem? Finally, we have to think about how? How are they becoming infected? How are they developing the condition that we're interested in? So, we need to know all of these things if we really want to act to prevent. Surveillance data, can tell us many of these things and that's why it's so important. A good way to think about how we act on public health data, is to review the public health surveillance cycle. If you go to the link below, the US, CDC has an introduction to public health surveillance where they talk about the public health surveillance cycle. What we've shown, here, on this slide is, a kind of, adaptation of the cycle that they describe. So, once you've decided on a public health event that you're intent on monitoring or prevention and action, the first thing you do, any of those public health surveillance cycle, is collect data. So, public health surveillance starts with data collection. This could be collected by the public health department, people could be reporting these data in. There are many different types of data collection, but first you start with the data. The raw pieces of data themselves. The next step is to analyze the data. Data analysis, is sometimes done periodically, sometimes it's ongoing. It depends on what your goal for the public health surveillance is. But that's the next step is taking these data that come in from your system, and analyzing them in a way that will help you understand the who, where, when, why, and how of what's going on with the public health event that you're interested in. Once you're finished with the analysis, well, then you move to data interpretation. So, what did the analysis mean? What do the trends show? Is the problem getting worse or is it getting better? What are the patterns that we see in terms of person, time, or place from that analysis that are going to help us intervene on this public health problem? From there, we move to results dissemination. So, we've collected data, we've analyzed the data, to answer our question. We've interpreted the data. But now, if we want action, we need to share that data interpretation. We need to share the results with the people who will take action, and we have to disseminate those results or share them in some way. How do we do that? Well, we can make them publicly available. That'll give them to the public, but maybe we need special meetings with policymakers, so that they can understand what the data interpretations are, so that we could suggest what they may do to act. It all depends on who we want to act on the data. Whoever we think should be acting on the data is who we should focus on for our dissemination efforts. This is a pretty simple concept to grasp, but in practice, it can be quite difficult. Some public health surveillance cycles, the people collecting the data are the same ones, really, who need to understand it most, but that's not always true. Sometimes, you have to work across organizations and get people's attention with the data if you want to make the ultimate link to action. So, once we've disseminated results, hopefully, then you are getting a link to action. The whole purpose of public health surveillance is to get to this action piece. If we're not acting on the data, then it's not truly a public health surveillance system, because a public health surveillance system is not designed for data collection purposes alone. There has to be this action piece. Who acts? Again, action could be at an individual level, but typically, we're looking for action at a systemic level. We're looking for public health agencies to introduce new policies or programs. We're looking for people who are in a position to change public health or medical practice, to do so based on the data, and the results that have come out of our surveillance system. That's our ultimate goal. You'll notice that the link to action goes back to data collection. So, we're right back where we started. Why is that? Again, it's a cycle. It's not just the line from data collection to action. But once we get to action, that may also influence the type of data that we're collecting. Now, let me give you an example. Let's say, for instance, that we are collecting data on a particular infection. We analyze the data, showing who's getting infected, when, and where. We interpret those data and disseminate them to policymakers, and policymakers take action, and they implement new public health programs to stop that infection. Well, then, we may change our data collection systems a bit after that program starts, to be sure we can monitor changes over time as a result of that new public health program, or perhaps we have new information from that action that different age groups are at risk and we hadn't previously included them in our public health surveillance. We may want to change who we're collecting data from, we may want to change where we're collecting data, all of these things are amenable to change. So, public health surveillance systems aren't always static. They do change and they should change based on the public health needs and what type of action we're taking.
