The Earth is an Antioxidant P < 0.05

A week ago, a new study published in Frontiers Physiology titled, “Effectiveness of Grounded Sleeping on Recovery After Intensive Eccentric Muscle Loading” investigated the effects of grounding on recovery in athletes.1 What the Heck Is Grounding? For those who are unaware of what grounding is, the authors give a very brief explanation here in their introduction, Grounding, earthing, or grounded sleeping, is a process in which the athlete becomes grounded via an electrically conducted device. Read More

When Can We Say That Something Doesn’t Work?

People don’t want to waste their time on things that don’t work. To avoid wasting time, many may want to assess the scientific evidence. They may first look at the basic science (if it can be studied at such a level) and ask, “does this thing have a clear molecular/biological mechanism,” or they may ask, “does it have a theoretical foundation?” Next, the person may look at the human evidence (if there is any) and ask if it worked in a clinical trial or epidemiological data. Read More

Book Review: Fisher, Neyman, and the Creation of Classical Statistics

Erich Lehmann’s last book, which was published after his death, is on the history of classical statistics and its creators. Specifically, how his mentor Jerzy Neyman and his adversary Ronald Fisher helped lay the foundations for the methods that are used today in several fields. This post is intended to be a general review/summary of the book, which I recommend to everyone and anyone who is interested in statistics and science. Read More
fisher  math  power 

A Critical Look At The REDUCE-IT Trial

It’s finally here. The results of the REDUCE-IT trial were presented today at the American Heart Association conference and the paper is also up on The New England Journal of Medicine. I’ve been excited to see the results of this trial ever since the announcement in September (which I wrote about here) so let’s get right into it. I’ll just copy and paste what I’d written before in September regarding the inclusion/criteria and statistical analyses so that I can get right into the results. Read More

P-Values Are Tough And S-Values Can Help

The P-value doesn’t have many fans. There are those who don’t understand it, often treating it as a measure it’s not, whether that’s a posterior probability, the probability of getting results due to chance alone, or some other bizarre/incorrect interpretation. [1–3] Then there are those who dislike it for reasons such as believing that the concept is too difficult to understand or because they see it as a noisy statistic that provides something we’re not interested in. Read More

We May Not Understand Control Groups

It’s well known that randomized trials are some of the most efficient ways to make causal inferences and to determine how much something (an intervention) differs from the comparator (some sort of control). Random assignment helps make these goals easier by minimizing selection bias and making the distribution of prognostic factors between groups random (not balanced). [1] Discussions (similar to the one above) praising the efficiency of randomized trials are widespread, however, few of these discussions take a close look at some of the common assumptions that individuals hold regarding randomized trials. Read More

Analysis Issues In That New Low-Carb/LDL Study

Recently, a randomized trial that investigated the impact of a low-carbohydrate diet on plasma low density lipoprotein cholesterol (LDL-C) in young and healthy adults was published. The study was done in Norway between 2011 and the end of 2012. A total of 30 participants completed the study, where they were either randomized to a low-carbohydrate group (<20 grams/d) or a control group. Basically, the investigators found a difference between the groups, Read More

Influential Errors | The Diet Heart Tale

Earlier this year, my colleagues and I were discussing the relationship between saturated fat and cardiovascular disease. One of us was writing an article on the topic and we were discussing an unusual trial often included in meta-analyses. That trial is the Finnish Mental Hospital Study, a crossover study that compared patients on a control diet with a certain amount of saturated fat to patients on an intervention diet that replaced the saturated fat with polyunsaturated fats. Read More

Misplaced Confidence in Observed Power

Two months ago, a study came out in JAMA which compared the effectiveness of the antidepressant escitalopram to placebo for long-term major adverse cardiac events (MACE). The authors explained in the methods section of their paper how they calculated their sample size and what differences they were looking for between groups. First, they used some previously published data to get an idea for incidence rates, “Because previous studies in this field have shown conflicting results, there was no appropriate reference for power calculation within the designated sample size. Read More

The Rise, Fall, and Rise Again of Fish Oil?

With the exception of this past week, it hasn’t been a very good year for fish oil. In early 2018, a large meta-analysis and systematic review of several randomized trials was published in JAMA. This large pooled analysis (77,000 + participants) assessed the impact of supplementing fish oil on cardiovascular disease events and found that there was no statistically significant effect (p=.10). The relative risks (RR) and coverage of the confidence intervals (CI) also suggested a very small effect (RR: 0. Read More