I'd like to provide you another example. In this case, regarding a volcanic eruption that happened in the City of Goma in the eastern Democratic Republic of Congo in 2002. Here is a enhanced satellite image showing the Nyiragongo volcano. It didn't exactly erupt in the traditional sense in 2002, there actually was an earthquake, the volcano split at the bottom and lava poured out of the bottom of the volcano not the top of the volcano. I didn't know this about lava because in this area, in the eastern part of Congo, there have been dozens of major volcanic earthquakes in the centuries past. The ground is mostly old volcanic lava that has now solidified. So when the hot lava pours across the ground, it actually melts the old lava that's underneath. Thus, as you look at this picture, you can see the lava flow is completely below the surface of the ground. It's melting a trough and flowing downhill as it goes, and maybe that trough is three meters deep, maybe it's four meters deep, and one of the strands went right through the middle of the town of Goma. You can imagine if you are melting the ground for a two meters or three meters down, as you do this, you will be cutting all of the water pipes in the City. Thus, the water plant, as you look at this picture of Goma, is at the top of the picture where you can see that little peninsula sticking out at the top of the picture. That's where the water plant was and half the population was being cut off from the water plant by this lava slicing through the distribution system. So the volcano erupted on January 17th, of 2002, right away perhaps 300,000 people ran across the border into the country of Rwanda. The volcano stopped flowing in the days that followed, and probably, by three days later people started returning. Right away, a couple of local groups started setting up schemes to provide water points. Those water points really had three goals. The first goal was making sure people got enough water. The second goal was making sure people had safe water. Most importantly, the third goal was making sure people didn't drink untreated lake water. The reason is because just eight years earlier the worst cholera outbreak ever recorded happened in the town of Goma and it was associated with people drinking untreated lake water. Probably, 30,000 people died over a two-week period. Probably, something in the order of half a million people were infected, and so they're relief community had three goals with these water points. It turns out in 1990 for eight years earlier the worst cholera outbreak ever recorded happened in the city of Goma. It happened from people drinking untreated lake water. It appears that cholera is endemic in the lake that is always there and it has an ecological host out in the environment. Thus, everyone was very worried that we would have a repeat of this terrible cholera outbreak and wanted to avoid that at all costs. So the goals were making sure people had enough water but making sure that water was safe primarily chlorinated, and most importantly, making sure that people didn't drink lake water that was untreated. So right away, within just a few days, a series of water points were established. Shown by the little green dots on this map, which is a simplistic drawing of the city of Goma. At each of those points, there was a water bladder set up. I'll show you a picture in a moment. Beside the water plants, there was a filling hose organized so that tanker trucks could be filled by water, chlorinated water, from the water treatment plant that was largely cut off from the rest of the City because the pipes had been melted by the lava. Then that water was brought out to bladders. Shown earlier by those little green dots on the map. At each bladder, they would set the bladder up just a little bit higher than the ground and make it so that water would run by gravity out of that bladder and people could fill up their containers with this chlorinated water coming from the water plant. So here's a water point and here's a really busy water point. You can see that there are hundreds of people queuing up to collect water here. Separate from the providing of water bladders which tanker trucks were delivering the water to, was the issue that people were going down to the lake and collecting water with jerry cans on their own. Here was a Congolese fellow who worked for a local NGO and he's actually injecting a little bit of chlorine concentrate into all of these water containers as people collect their water. So another element of this program to avoid people drinking unsafe water was these bucket chlorinators down by the edge of the lake. In that organization, that was chlorinating water along the lakes edge, actually operated in eight locations. Here is their data of how much water shown over on our left axis they were chlorinating per day at each location. Notice, if you combine all of the locations where they work, they're chlorinating hundreds of thousands of liters on most days. So here is Ami Kivu's estimate of the total water they chlorinated beside the lake. On two different occasions, on the 26th of January, and on the 31st of January, I went out and I did a survey with a team of people on the lakes edge and tried to estimate how much total water was being collected. So we could compare the tonal water collected with how much water they were chlorinating. You'll notice that on the 25th of January, only about half the water that we think was being collected at the lake was being chlorinated. But by the 31st, It was the vast majority of water being collected. So here, we're looking at with the little triangle survey data, and with the blue squares, the horizontal line is ongoing surveillance data, tabulated by the people that are actually chlorinating the buckets. We also did surveys of households. We did this by walking a grid over the city because we weren't sure where people were at that moment in time. We asked about their access to water and where they had gotten their water on the day before. How many people were in the household? If they had a toilet and we asked specifically, how much water did you collect yesterday at water bladders that they may have visited. So because we did this survey repeatedly we could figure out trends over time. Here is a table showing the three surveys that we did and what I most want you to note is that in the second to bottom line, the amount of water people collected stayed pretty steady, but if you look at the third line they were collecting more and more water. So this is actually a system where as more and more people were slowly trickling back to their homes, the relief system was getting better and better and better providing more water but it didn't look better on a per capita basis, but at least we were somewhat keeping up. Now here, is a graphic showing the number of water consumers using lake water in the solid line, and the amount of water people were collecting in those bladders that was tankard in the dotted blue line. You'll notice as time goes on, people are consuming less lake water and more tanker water. So as time went on even though per capita consumption was staying about the same, we are moving from an unsafe source to a safe source. So as we look at the various places people were getting water, we can see that on the bottom the amount of water they're getting from the lake was going down steadily over this couple weeks of the initial crisis. If we combine the notion of less water being taken from the lake in the bottom graphic with the fact that in the beginning half the water they were collecting wasn't chlorinated but by the 31st the end of January it was mostly being chlorinated. We had something like a 99 percent reduction in the consuming of unchlorinated lake water over the window of time of this crisis. Remembering that outbreak in 1994, the relief community in '94 provided one liter of water at the end of two weeks. In this crisis, we ended up providing 10 liters by the end of the first week. That's really great. In that first crisis, we had a lot of deaths from cholera. We had not one case of cholera in 2002. So it was a really nice example where surveillance data and survey data together allowed us to do a really good job of delivering water, and monitoring the quality of the service we were providing. I'd like to leave you with a couple of conclusions and takeaway messages. So there are multiple needs that back-end health information in emergencies and they depend on the context and the crisis, and a lot of different things. The timeliness of the data, the quality of the data, the complimentary insights you need to interpret the data all vary depending on what your goals are and what you're setting is. Almost always data exist, but it's just hard to figure out how well is that data covering your needs. Speaking in great generalizations, surveillance data tends to have the huge advantages of being collected over time so it's arriving in a timely manner. People tend to believe it because it's being collected by doctors and nurses who they have faith in. It can often come with high-quality controls like confirming that certain cases really were cases, but surveillance data has huge disadvantages. It's almost always incomplete. It tends to be biased and maybe the people who live closest to our richest or of a certain group will be more likely to be detected. If things change over time rates can appear to change when they really do not. Surveys on the other hand tend to be more complete and less biased, but they can potentially be done badly. They're very easily dismissed. So we think of them as being better for advocacy and non-controversial issues, but there's one more really important reason why I think that we as a humanitarian community need to be collecting evidence and data on a regular basis. Here is a graphic. It was collected by a bunch of folks who worked at the Centers for Disease Control led by Paul Spiegel, and it's showing the deaths in Kosovo over a period of time in 1998 and 1999 when Serbia had invaded, had occupied. Then starting in the spring of 1999 NATO began bombing those Serb forces. You will see in the line with the open circles, a huge spike in violent deaths in the spring of 1999 that began after NATO started bombing. So NATO started bombing and that spike began immediately. Now, one of those recorded deaths by Paul Spiegel's team was from a NATO bomb. Because NATO started bombing the Serbs decided, "Oh, we need to leave," and they just started slaughtering particularly older men in Kosovo to punish them and finish their work before they left. A couple of years ago when it is likely that sarin gas was used in Syria, and Serb several western political leaders wanted to use targeted bombing to punish the Syrian government, this data that had been collected more than a decade earlier was the data that stopped that from happening because it showed you can use really smart bombs. You maybe will not kill any civilians but that doesn't mean you're not going to trigger violent revenge acts on the ground. So I'd like to leave you with the thought that in the long run, good data almost always trumps political bad leadership, and the most exacerbating frustrating parts of your crises, and it's important to be collecting data so that we learn hard lessons, and that the world can take your experience of witnessing and the hardship that you have been seeing, and use that health data for avoiding future crises. Well, I hope this has been helpful. There's a lot of work to be done. So I'll stop distracting you from it. Bye bye.