Building an experiment (4)
Day to day, symptoms can vary widely depending on a spectrum of inputs — food, sunlight, exercise, socializing, sleep — that have nothing to do with a given treatment. Extending the duration of each treatment block, boosting the number of treatment blocks, or increasing the frequency of reporting means experimenters gather more data. This can negate the effects of non-treatment effects, and boost an experiment’s statistical validity. Every experiment, though, depends on the experimenter’s tolerance for continuing, so most experiment designers compromise on a duration that seems to the person being tested.
Some single person experiments includes “blinding” — making each treatment appear the same to reduce a psychological biases for or against each version. (Knowing that a treatment is newer or a stronger dosage can boost its perceived effectiveness by an average of 9% versus a control.)
Doctors can instruct a compounding pharmacist to create a double blind by putting different treatments or strengths (or a placebo) into identical pills or liquids. The bottles can be sequentially labelled (for example 1, 2, 3, 4, 5, 6) so that neither you or the doctor know which treatment you’re taking in a given time period.
Once the experiment is over, the pharmacist can provide a key that reveals which code corresponded to which treatment. (This might reveal, for example that you’d taken six successive weeks of A, B, B, A, A, and finally B.)
Particularly for nonpharmaceuticals, some people ask a friend to help with blinding by distributing different treatments into identical containers. This is simple for oils—for $6.99, you can buy 25 plastic dropper bottles or six glass dropper bottles. Funnels are available too. The same goes for ointments and creams—five jars cost $10 on Amazon.
The friend might label each as A, B, C, D, E, F (one for each treatment period using the schedule you pick) being careful to separately note which treatment went into each container, and then pass the containers over to you.
(Historically, not that not experiments include blinding, particularly when it’s impossible to create seemingly identical versions of each treatment, for example when a treatment involves obvious physical alterations.)
Just like everybody is different, every treatment is different. Here are some links to trials using a variety of treatment block durations.
Melatonin: 2 weeks treatment blocks (sleep in Parkinsons); 4 weeks (sleep in alcohol dependence); duration of hospital stay (delirium in elderly patients); 30 days (inflammation in athletes); 21 days (sleep). More melatonin studies.
Caffeine: 2 and 4 week treatment blocks (insulin resistance);
Including a placebo in an experiment helps tease out the often powerful psychological effects of being treated.
But often placebos are difficult or impossible to implement, particularly if the treatment has physical manifestations (tingling, scars) that lead to unblinding or there’s no compounding pharmacist is available.
In some cases, unblinded personal experiments without placebos have yielded the same results as large, expensive gold-standard trials with blinding.
Finally, its important to note that placebo effects can be both positive or negative.