How VitaSync finds connections in your data

The Insights tab is the reason VitaSync exists. It looks across everything you track and points out the things that tend to move together. Examples are shorter sleep and higher spending, or more steps and a better mood. This guide explains how it decides what to show you. It also explains why it would rather show you nothing than something it cannot back up.

What a connection is

A connection is two things in your own logs that rose and fell together more often than you would expect by chance. It is an observation about your past days, not a verdict on what causes what. That is why every finding is worded as “tended to” or “moved together”, never “because”.

If late coffee and short sleep keep turning up on the same days, that is worth knowing. Whether the coffee is the cause, or a stressful week is driving both, is something you can then test for yourself.

How it compares two metrics

VitaSync uses a rank correlation. Instead of comparing raw numbers, it sorts your days from lowest to highest for each metric and checks whether the orderings line up. That has two useful effects:

• Different scales compare fairly. A 1 to 10 mood score, hours of sleep and pounds spent can all be compared with each other.
• One extreme day cannot dominate. A single blowout weekend moves a ranking far less than it moves an average.

Days you did not log are left out, never counted as zero. A missing mood score is not a bad mood.

How much data it needs

A pair of metrics needs at least 21 days where both were logged before it can appear as a connection. Other findings wait longer: weekday patterns need about four weeks, for example. Until then, the tab tells you how many more logged days it needs instead of guessing.

That wait is deliberate. With a week or two of data, almost anything can look related.

How sure it is

Every connection comes with a strength and the number of days behind it, for example “moderate, based on 34 days”. Behind that line, VitaSync works out a 95% confidence range for the relationship. If that range includes no relationship at all, the pair stays hidden, however striking it looks.

There is a second trap. Track twenty metrics and there are 190 possible pairs, so a few will look related by pure chance. To allow for that, findings are ranked by the cautious end of their range rather than their best case. The tab shows fewer findings when fewer survive. Three honest connections beat a page of noise.

Next-day effects

Some things show up a day later. A short night can line up with a low mood the next day rather than the same one. VitaSync also checks each pair with one metric shifted by a day. It labels the finding as next-day when that is where the pattern is strongest.

Testing a change

Once a connection makes you curious, you can run an experiment. Pick a change, such as no alcohol for a fortnight, and VitaSync compares that period with the 30 days before, using the same confidence rules. It still reports what changed rather than claiming why.

Where the maths happens

Insights are calculated on your phone, from the data stored on it. Your numbers are not sent anywhere to be analysed, and the product analytics we collect never include your values. If you switch on backup, your data is synced to your own account so you can restore it on a new phone.

The short version

1. It compares the order of your days, so different kinds of numbers compare fairly.
2. It waits for enough days before saying anything.
3. It hides anything it cannot be confident about, and allows for the number of pairs it checked.
4. It describes what moved together and leaves the why to you.

Not sure what to start logging? Read what to track first.