{"id":18432,"date":"2022-06-10T09:20:08","date_gmt":"2022-06-10T08:20:08","guid":{"rendered":"https:\/\/www.economicsobservatory.com\/?post_type=question&p=18432"},"modified":"2022-06-10T09:20:09","modified_gmt":"2022-06-10T08:20:09","slug":"picture-this","status":"publish","type":"question","link":"https:\/\/www.economicsobservatory.com\/test\/picture-this","title":{"rendered":"Picture this"},"content":{"rendered":"\n

Newsletter from 10 June 2022<\/strong><\/p>\n\n\n\n

\u2018Photographs are a way of imprisoning reality\u2019, wrote Susan Sontag in her 1977 collection of essays, On Photography<\/em><\/a>. Photos capture a moment in time, presenting a portion of the world trimmed neatly into a single frame. The information omitted from the image vests great power in the artist behind the lens.<\/p>\n\n\n\n

What does this observation imply for economists? Working with data, like taking pictures, requires us to make choices and accept limitations. Just as a photographer has to decide what is in the frame and what is not, data scientists, economists and policy-makers must choose what questions to ask and which data to collect, analyse and present.<\/p>\n\n\n\n

Like photos, data become less relevant to the present day from the moment they are collected. Every day, thousands of people die and thousands more are born. As a result, the national census is out of date when it is only a day old.<\/p>\n\n\n\n

Recognising the strengths and limitations of data was the subject of a talk by Hannah Fry (University College London) at Bristol Data Week<\/a>. Hannah\u2019s talk \u2013 hosted by the University of Bristol\u2019s Jean Golding Institute<\/a> \u2013 explored a collection of her favourite data stories, focusing particularly on cases of where things were not as they first appeared.<\/p>\n\n\n\n

One example was the 1989 Challenger space shuttle mission<\/a>, a disastrous episode for the National Aeronautics and Space Administration (NASA). The story goes that the American space agency was deciding whether to launch on a scheduled date. Conditions were set to be very cold, at around 40\u00b0F (about 4\u00b0C). Thinking this could be risky, the team\u2019s engineers presented their superiors with the spacecraft\u2019s performance data from various launch tests, using a chart that plotted system failures against air temperature.<\/p>\n\n\n\n

During the tests, the shuttle had failed seven out of 24 times, at varying temperatures. To illustrate this, the engineers plotted the number of incidents on the y-axis against the air temperature on the x-axis. The points showed no clear trend beyond a vague u-shape, with failures seeming unrelated to weather conditions (see Figure 1).<\/p>\n\n\n\n

Figure 1: Number of incidents of damage by temperature<\/h4>\n\n\n
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