[SiVal]

Because of the selection process. If you are trying to make a judgment about an entire population based on a small sample, the chance of getting a non-representative sample is already high. If the sample is selected on the basis of what sticks out in memory, the chance of it being representative is almost nil. Though an interesting anecdote or two can be considered data, they are notoriously unreliable as a basis for statistical judgments.

[pbhjpbhj]

I think any reasonable approach realises that anecdotal evidence needs weighing appropriately. In the sibling comment for example if you merely wanted to establish if there are any incidences of children with "social awkwardness" that are home-educated (or if for example this is a product of a particular method of schooling) then you've got your tentative result off the bat. The fact that there are some such results allows you to hone your null-hypothesis and tune your approach to getting statistically significant data.

Anyway, I digress, anon.