How can light travel more than 13.7 billion light-years in 13.7 billion years?
William B. Keith
Houston

THE EDITORS REPLY: Space is expanding, carrying objects such as galaxies and photons with it, so light travels a greater distance than a simple calculation (such as speed multiplied by time) might suggest. An object that emitted light 13.7 billion years ago is now 42 billion light-years away. This figure depends on the values of cosmological parameters.

STATISTICAL SUGGESTION
As a biostatistician, I concur with Charles Seife’s critical comments about the abuses of the so-called p-value as a measure of statistical significance of data in “The Mind-Reading Salmon” [Advances]. Statisticians have criticized this methodology before, sometimes even recommending banning it. I would temper such criticism, however, by pointing out that there are a variety of adjustments to p-values to take into account the kind of multiple-testing artifact Seife refers to, and they are often used (though perhaps not as much as they should be).

Another issue relevant to this topic is the publication bias of many journals, which often give greater weight toward publishing articles that report statistically significant findings over those that don’t. I have advocated before that one way to mitigate problems with null-hypothesis significance testing is for editors of scientific journals to employ “results blind” decision making in determining whether to publish and make it be known that they are doing so. Articles should be accepted for publication based primarily on the judged importance and relevance of the reported study, which is usually stated and defended in the “introduction” section of the manuscript, and whether the methodology (including that of the data analysis) is sound, which can be assessed via the “methods” section of the manuscript.

With this kind of review process, if 20 studies of the effectiveness of a truly ineffective drug are conducted, and one of them shows a significant effect with a p-value of 0.05 because of chance alone, investigators for the other 19 studies not showing any effect would presumably not be inhibited from writing up and submitting reports of these for publication out of fear that they’ll be denied publication because of their nonsignificant results. Publishing of those results would then cause the scientific audience to be rightly skeptical of the one significant finding amid the many reports not demonstrating it.
Joseph J. Locascio
Instructor in Neurology
Harvard Medical School

4 Comments

1. 1. ufologist 10:36 AM 12/2/11

   Obviously better policing contributed to the decline in crime in NYC, but the considering the timeline and the targetted demographic, I'd imagine that the enormous social-shift that occurred then has more to do with the decrease in crime rate than any strategy implemented by the NYPD, especially considering the decrease in the national crime rate at the same time...
   
   This social shift often called the cocooning-effect was largely driven by the rise of videogames as a form of entertainment for that particular age group. I'd imagine that you could even find an inverse-correlation between popular video game release dates and downspikes in violent crime.
   
   
   
   
   

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2. 2. ufologist 10:44 AM 12/2/11

   Okay... well after a google search I found a paper related to what I was thinking... their conclusion is that violent video games are linked to decrease violent crime, which is a step further than I was going to go... I haven't read it yet but their conclusion is that violent video game have an incapacitive effect on would-be violent criminals:
   
   ftp://ftp.zew.de/pub/zew-docs/dp/dp11042.pdf

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3. 3. eco-steve 05:40 PM 12/4/11

   The longer governments treat workers as an expendable merchandise the more poverty and hence crime will increase.

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4. 4. HubertB 08:01 AM 12/9/11

   I worked in a prison library. A number of the men, black men especially would say to me, "You are the first adult man I have ever known. I never before knew how grown men behaved. Grown men act totally different from the way I thought they acted. When I get out, I am going to act like you act and not come back to prison."
   These men had grown up and gone through school for at least 10 years without ever being exposed to an adult male. They had been raised in a matriarchy. All of their teachers and librarians had been female. They had no idea how any adult male behaved in a casual relationship other than a gang leader. I did not react the same way as their former female leaders. Most of them shaped up.
   That ended when the governor fired a number of librarians.
   Today I am frequently stopped on the street. A large black man will say, "Thank you Mr. B... Because you had confidence in me, I am now going straight."
   Perhaps this country should rethink its policies preventing boys living in matriarchies from having an official adult male influence allowing males to have paid jobs in government positions. Relying on volunteers has not done it.
   

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