There’s a great deal of anecdotal reportage citing yoga as complementary medicine, but there is a vast difference between personal stories and hard science. If you want to truly understand the current state of research regarding yoga, it’s important to read critically. It’s also important to comprehend what makes science good or bad.

Hard science requires thinking that goes beyond personal anecdotes. To be accepted by the community of medical scholars research needs to be valid. This concept refers to a study’s accuracy – does it measure what it claims to? Studies that look at large groups of people are more likely to be indicative of the population at large.

Another reason for looking at a large group of people is to make sure that the results are statistically significant. Statistics is a branch of mathematics that measures numerical data, and for something to be statistically significant means that the results happened enough times numerically to make them stand apart from mere chance. While you or I might feel that our yoga practices keep us calmer, scientists want to find that this happens to enough people that they can recommend yoga to the general public.

Reliability refers to the ability of scientists to repeat the study more than once and get the same result; this is another way of making sure that the results truly fit the claims. If I am looking for an exercise program that will help my knees, for instance, scientists want to be able to tell me that they’ve looked at the practice a number of times and have indeed discovered over and over again that asana builds strength there. The larger numbers thus suggest greater accuracy for the study.

Correlation is not causation! This is an important precept of scientific research. Simply put, it means that two things happening in order are not necessarily related. In a perfect world, a randomized study divides participants into two different groups in a completely arbitrary way. One group is given the treatment, while the other one isn’t. Also ideally, everything else about the two groups should be the same. This ensures that the treatment is indeed the variable that makes the difference rather than outside issues. When looking at yoga, for example, scientists need to make sure that asana or meditation is what’s causing the change, rather than the fact that participants are vegetarians, take vitamins, or engage in some other lifestyle variation.

Finally, the best scientific studies are peer reviewed. Before being published, they are read and analyzed by other scientists that are not connected to the research. If the reviewers feel that the study passes muster, it’s then published. This is another way that science attempts to make its findings truly objective.

It’s wonderful to love yoga, and to be excited about what it can do for our lives. Bringing scientific rigor into yoga studies ensures that efficacy claims are more than personal opinion. Understanding how scientists safeguard rigor allows us to read the research with greater confidence.