Studies testing the same hypothesis will tend to find results that match the underlying true effect, but there will be some variation in their results due to differences between studies (different participants, researchers, settings, and so on).
However, varying reporting behaviour leads to discrepancies between self-assessed health and the underlying true health.
According to this, reported health in those countries is overrated compared to the underlying true health.
As for surveys in general, results can only be considered as a sample of an underlying true population.
When the underlying true function is in certain Besov and Hölder classes, the resulting estimator achieves the minimax rate of convergence.
This thus creates "crowding" when a linear technique such as MDS is used, but could additionally entirely misrepresent the underlying true topology.
As the simplest case we can assume that the probability of errors is the same for all subjects and independent of the underlying true preference pattern.
This may result in systematic differences in the stated health across population subgroups, even if the underlying true health status is identical.
These methods provide a first illustration of the data with as few assumptions as possible on the underlying "true" firing rate.
This "fringe resolution" is known to be an imperfect measure of resolution in TEM [25], but remains useful for discerning trends in the underlying "true" resolution.
The red polygons show the location of the field transects within the study areas with underlying true color Rapid Eye imagery.
