Non-ignorable missingness

Statistics is basically a missing data problem! – Little 2013 Nearly all samples – whether by design or by accident – are incomplete. We very rarely make a complete census of all individuals in a population or all sites on a landscape. Sometimes we don’t collect, or can’t collect, complete information for individual samples or measures. For instance, we might know an animal was alive when it was last seen, so we know it survived at least that long, but know nothing about its current status. ...