1 posts
False positives with prenatal tests for rare conditions

Sarah Kliff and Aatish Bhatia for NYT’s The Upshot look at the uncertainty of prenatal tests for rare conditions. For some tests, the results are more often wrong than they are right, which causes issues when expecting parents don’t know that. Along with square pie charts, the piece goes into more detail with unit charts to explain what the percentages mean from a counts point of view. So if a...

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Student surveillance and online proctoring

To combat cheating during online exams, many schools have utilized services that try to detect unusual behavior through webcam video. As with most automated surveillance systems, there are some issues. For The Washington Post, Drew Harwell looks into the social implications of student surveillance: Fear of setting off the systems’ alarms has led students to contort themselves in unsettling ways. Students with dark skin have shined bright lights at their...

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Increased case counts not just from increased testing

Some attribute increased Covid-19 case counts to increased testing. While that is certainly part of the reason, it doesn’t explain it all when you compare testing rates against the increase in positives. Charles Ornstein and Ash Ngu for ProPublica: In other states, including Arizona, Texas and Florida, which did not see a wave of early cases and deaths, the increase in positive results has far surpassed testing growth. In Florida,...

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Bad denominator

With coronavirus testing, many governments have used the percentage of tests that came back positive over time to gauge progress and decide whether or not it’s time to reopen. To calculate percentage, they divide confirmed cases by total tests. The denominator — total tests — often comes from the CDC, which apparently hasn’t done a good job calculating that denominator, because not all tests are the same. Alexis C. Madrigal...

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Coronavirus testing accuracy

Medical tests do not always provide certain results. Quartz illustrated this with the accuracy of a simulated antibody test that identifies 90% of those infected and 95% of those not infected: That means that if you took the test and got a positive result, there’s a 45.1% chance it’s correct. If you got a negative result, there’s a 99.6% chance your result is accurate. Of course, this doesn’t mean don’t...

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Lagging coronavirus testing in the US

Coronavirus testing in the United States has been a slow process to say the least. The New York Times shows how test counts contrast against other countries. There’s some catching up to do. Tags: coronavirus, New York Times, testing

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