Of course negative information has value. The question is if and how to record it. Here is the conundrum: If we start recording negative values we will need to do that consistently. In other words, the patient didn’t have a heart attack today, didn’t have one yesterday, didn’t have one the day before, etc. You would have to list everything that didn’t happen. Or define eras of things that didn’t happen. The size of your data store would quickly be measured in petabytes. There is a reason we don’t do it that way: Most things don’t happen (thank God).
What you perhaps meant to say is that negative information makes sense for permanent types of information, like the allergies and family history. So, you’d only record that once, correct? Except these things tend to also change, allergies can be developed, and your parent might fall ill with a new disease.
The next idea people have is to record a negative fact when the positive facts are not reliably determined or captured. So, the explicit information “no lymph nodes affected” in a cancer is a different information than if nobody looked. And often this is the case.
The problem is nothing is ever 100% captured. No concept has a 100% sensitivity. But we are relying on it anyway for observational research: to calculate rates and relative risks of things. With the exception of the MEASUREMENT table we assume:
Axiom 1: If there is a record it happened
Axiom 2: If there is no record it didn’t happen
Axiom 2 is where we routinely get in trouble. What we really need is a systematic way to determine sensitivity and specificity of every concept, and then bake these into our statistics.
Adding negative records will throw is into an abyss: All methods and all cohort definition practices would have to change. We would always have to do both: “Give me all patients who had an heart attack” and also “Exclude all patients that have an explicit record that they didn’t have an heart attack”. Setting the right timing of the latter alone would drive us crazy. And we would for sure get a huge number of contradictions.
Let’s not go there.