# How is significant change determined?

## Learn how significant change and similar concepts (MDC, SWC) are approached within the platform.

### The Long Answer:

When it comes to identifying "meaningful" or "significant" change in data, there are a lot of different thoughts and opinions that often confuse practitioners. Things that are statistically significant are often practically irrelevant so it is critical for practitioners not to get too bogged down in academic jargon while still ensuring best practice to remain objective and scientific.

We can do this by simply understanding two concepts: means (average) and standard deviations (variation). The MHP identifies significant change for an individual by first comparing the change in between the results to the historical variance for that metric. This is a widely used concept in human biomarkers, with terms like Minimum Detectable Change (MDC) or Smallest Worthwhile Change (SWC) often utilized in the literature to identify what may be considered a ‘real’ change as opposed to normal human variability. For this, we leverage our extensive repository of data to define a reliable baseline variance for the metrics. For each metric, the average standard deviation per subject is taken over a 14-day rolling window and then averaged across all subjects to generalize for the population.

A change in score is considered significant if the difference in the current score compared to the individual’s previous score is greater than the baseline of variance for that metric.

The greater the variation, the more spread out the data is, and in turn, the greater the standard deviation (a measure of the amount of variation) will be. We do this individually for each metric because various metrics have different amounts of expected variation. For example, a 0.1 change might be considered significant for a sprint time (4.50 compared to 4.40 seconds) but not so much if we are looking at a bodyweight change (225 compared to 225.1 lbs).

Significant changes are visually highlighted within the Movement Health Platform using arrows, to ensure Admin users are aware of any significant changes that are taking place for an individual.  It is important to note that changes can either be viewed positively (improvement) or negatively (deterioration), and the interpretation is, as always, context-dependent.

As seen above, the MHP will visualize a significant change utilizing an arrow up or down; meanwhile, it will also display the absolute change for the score. In the above example, we can see that a decrease of 5 for this user's Sparta Score would be considered significant, while the decrease in Balance of 3 is not.