Limitations of Science in Medicine

The insight gained from scientific experiments is limited by the degree to which all factors affect the results of a study can be controlled. When human subjects, researchers, and sponsors are involved things get complicated. Even well-designed trials with a sufficient number of participants for statistical analysis can be difficult to reproduce. Meta studies that review all existing clinical studies that answer the same question often come up with a summary that looks like an election result rather than an example of the consistency of scientific method.

Individual Patient Response to Treatment

Even when we have good agreement across studies, for example about the effectiveness of a medical treatment, we are looking at average results for large groups of patients. It happens frequently though that two patients with the same diagnosis respond very differently to the same treatment. They may respond at varying degrees or not at all. One patient may experience severe side-effects and another does not have side effects at all. Usually there is no way to predict with certainty how an individual patient will respond to a given treatment. For some medical treatments the expected response rates are around 30%, which means that only about one in three patients will respond to the prescribed treatment. That’s why it would be ideal to track treatment outcomes for each patient to ensure that the treatment is effective, can be fine tuned, or substituted if the desired results are not achieved. Individual outcome tracking will also enable us to uncover signs of unexpected adverse events much earlier and therefore improve patient safety. Eventually medicine will be able to employ individual information to enable better treatment predictions and decisions. For example, the availability and understanding of a patient’s genetic information will allow us to deliver a more personalized treatment that achieves more consistent treatment benefits.

Pragmatic N = 1 Studies to Enhance Individual Care

While the use of genetic information lies in the future of personalzied care, there is a lot we can already do today by better measuring, analyzing, and following up on how an individual patient responds to treatment over time.

Even if systematic outcomes tracking is not done yet in a regular care setting, given the broad availability of tracking apps and sensors, it is possible for most patients right now to

  • raise their well-being
  • better understand their own health dynamics
  • compare over time what worked and what didn’t
  • try out mind and body hacks (interventions) to better support treatment


The scientific approach that allows this is a “n=1” study. It’s a study that only has one patient enrolled and is rooted in sequential assessments. The goal of this method is to achieve the best health result for one patient, rather than to provide an average result for an entire patient population. However, N=1 studies also have the potential to discover interesting hypotheses that then can be later tested in populations. This approach is fairly new in medical practice, but I expect it will become widely used as patients embrace mobile apps and wearable sensors.

TracknShare Apps and the Quantified Self

Over the last years I worked on several projects to move the N=1 field forward. In 2002 I hacked into electronic key-chain devices and portable barcode scanners to build a portable symptom and therapy tracker. In 2009 I started to make iPhone and iPad apps for individual outcomes tracking. In 2011 I presented these projects at the first global Quantified Self conference in Palo Alto. Find out more here:

Evidence-based Medicine and Medical Practice Today

While evidence-based medicine is the gold standard medical professionals have to rely on, many areas of medical practice simply are not yet backed up by scientific evidence. When a patient presents with problems doctors need to help.

They rely their own experience, medical reasoning, intuition and practice guidelines. Medical guidelines usually describe the current standard of practicing medicine. Guidelines are backed up by evidence where available, follow tradition, or simply represent an agreement between those who have the authority to define medical guidelines. This is simply the best we can do today while striving to grow the body of evidence-based medicine.

Scientific Method for Individual Placebo Use

As we just saw there are three issues that define the intersection of science and medical practice today:

  • Not all patients respond to prescribed treatment
  • n = 1 methodology is only scarcely used in regular care
  • Only some medical practice is in fact evidence-based

A solution that touches all three areas could mean for the care team to define Individual Treatment Plans (ITP) and to systematically track what works and what doesn’t. Such a systematic solution could also provide the framework for the use of honest placebo in regular care.

While we try to build such solutions within the healthcare system it is possible that patients will lead the way and embrace this approach on their own.

Possibly, the main advance in medical practice over the next 10 years will be driven by patients empowered with mobile apps and tracking devices, generating data on everything from prescription drugs, behavior, diet, supplements, and placebos.

For those who do not want load up on apps and sensors just yet, it can still be helpful now to start a practice of writing down what happened and what seemed to work, e.g., a symptom diary.