<instructions>Your goal is to analyze the following comment and estimate how highly it will be upvoted by the Hacker News community.</instructions><comment><author>tomp</author><text>Hm... judging by the cover, this looks like absolute crap.&lt;p&gt;&amp;gt; Some studies have shown a continuous decline in semen quality since the beginning of the 20th century.&lt;p&gt;Studies also indicate a continuous decline in testosterone (in males) over 20th century. I&amp;#x27;d welcome someone correct my biological knowledge, but I would guess that testosterone influences production of sperm, not the other way round. So they&amp;#x27;re probably studying the wrong thing.&lt;p&gt;&amp;gt; One postulated contributing factor is radio frequency electromagnetic radiation emitted from &lt;i&gt;cell phones&lt;/i&gt;.&lt;p&gt;So... how do you then explain the decline from 1900 until 1990?!?&lt;p&gt;&amp;gt; Questionnaires accessing demographic data and characteristics of cell phone usage were completed by 106 men&lt;p&gt;Trying to do statistics on a small, ...&lt;p&gt;&amp;gt; referred for semen analysis&lt;p&gt;... biased sample, seriously?!&lt;p&gt;I&amp;#x27;m too paranoidly afraid of the negative effects of radiation, but even I&amp;#x27;m inclined to call bullshit on this study.</text><parent_chain></parent_chain></comment><story><title>Habits of cell phone usage and sperm quality</title><url>http://www.rbmojournal.com/article/S1472-6483(15)00300-4/abstract</url></story>
<instructions>Your goal is to analyze the following comment and estimate how highly it will be upvoted by the Hacker News community.</instructions><comment><author>yummyfajitas</author><text>I can&amp;#x27;t critique the article directly, since it&amp;#x27;s behind a paywall.&lt;p&gt;But I can take the purported results and do some Bayesian analysis with it. Take first a prior - due to my knowledge of physics, my prior on microwave&amp;#x2F;RF&amp;#x2F;visual radiation having any biological effect is 10^{-5}. Multiphoton ionization has simply never been observed to happen except under extremely intense (read: it&amp;#x27;ll melt you) fields and there are strong theoretical reasons to believe it won&amp;#x27;t happen.&lt;p&gt;I.e., if this effect is real, it&amp;#x27;ll require new physics to explain. Most likely 10^{-5} is a conservative prior on the likelihood that an experimental paper overturns quantum mechanics.&lt;p&gt;Now, lets take their strongest result (p = 0.02) and do a Bayes update with it, assuming a complete absense of selection bias&amp;#x2F;etc (i.e. imagining this was a perfect RCT).&lt;p&gt;P(effect false | experiment result) = P(experiment result | effect false) P(effect false) &amp;#x2F; P(experiment result)&lt;p&gt;= 0.02 x (1-10^{-5}) &amp;#x2F; P(experiment result)&lt;p&gt;We can compute the latter as P(experiment result | effect false) x (1 - 10^{-5}) + P(experiment result | effect real) x 10^{-5} \approx 0.02 x 1.0. Assuming optimistically that the statistical power - aka P(experiment result | effect real) - is 0.99, the bottom is 0.020009700000000002.&lt;p&gt;Plugging and chugging yields:&lt;p&gt;P(effect false | experiment result) = 0.9995052399586201&lt;p&gt;Or equivalently P(effect real | experiment result) = 0.000494760041379938.&lt;p&gt;As a result, assuming you believe strongly in quantum physics (I do), this experiment provides wildly insufficient data to overturn QM and believe the effect is real.&lt;p&gt;Note: I&amp;#x27;m not explaining here why quantum mechanics says multiphoton ionization is a tiny effect, negligible in biological applications, I&amp;#x27;m just going to argue by authority: &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.chrisstucchio.com&amp;#x2F;publications.html&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.chrisstucchio.com&amp;#x2F;publications.html&lt;/a&gt;</text><parent_chain></parent_chain></comment><story><title>Habits of cell phone usage and sperm quality</title><url>http://www.rbmojournal.com/article/S1472-6483(15)00300-4/abstract</url></story>