Techniques for tackling survey error are many, varied and often complex (see, for instance, Groves 2004). Here we consider one particularly common form of adjustment: weighting. The remainder of this section considers one particularly common form of adjustment: weighting. This is a particularly useful strategy for dealing with unit non-response and relatively little or no information on the nature of the non-respondents. If you know that the distribution of your sample on a key variable (maybe but not necessarily the dependent variable) is different from official (accurate) sources, even if you are unsure of the source of the discrepancy or whether it is in fact an error in the survey, it is usually reasonable to weight your data to match the official marginal distribution for that variable. This could be simply for presentational purposes, but if the use of weights affects your substantive conclusions it is important to report how and why.