Tag Archives: data

Cancer Deaths – Declining Trend?

3,000 fewer cancer deaths:

Cancer deaths in the United States dropped for the second year in a row, health officials reported yesterday, confirming that the trend is real and becoming more pronounced, too.

The news was cause for celebration among doctors and politicians. “When we saw the first decline, the number wasn’t that enormous,” Dr. Felice Schnoll-Sussman, a cancer physician at New York-Presbyterian Hospital/Weill Cornell Medical Center said. “But once you start to see a trend like this, it obviously makes you feel like ‘We must be doing something right! ‘”

Is this really a trend? I have not examined the data at all but I seriously doubt it. People (the media even more so) constantly overreact to variation in data. Maybe I am wrong, certainly I should look at the data and see what it says – and I will if I get some time and remember. But I am more confident in my belief this is more overreaction to random variation than in the headlines. Why? Because so often when I do look more closely at the numbers my general observation of overreaction to random variation is confirmed while news reports talk of “trends.” Hopefully I am wrong this time.

Ok, I couldn’t resist and I did a little looking for some data. This is how crazy it is. The press release from the American Cancer Society states:
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Designed Experiments

One-Factor-at-a-Time Versus Designed Experiments by Veronica Czitrom:

The advantages of designed experiments over [One Factor at a Time] OFAT experiments are illustrated using three real engineering OFAT experiments, and showing how in each case a designed experiment would have been better. This topic is important because many scientists and engineers continue to perform OFAT experiments.

I still remember, as a child, asking what my father was going to be teaching the company he was going to consult with for a few days. He said he was going to teach them about using designed factorial experiments. I said, but you explained that to me and I am just a kid? How can you be teaching adults that? Didn’t they learn it in school? The paper provides some examples showing why OFAT experimentation is not as effective as designed multi-factor experiments.

Related: Design of Experiments articles – Statistics for Experimenters (2nd Edition) – Design of Experiments blog posts