A consistent finding is that elderly people obtain higher scores on social desirability (SD) scales than younger ones. It is usually assumed that elderly people are more eager to present themselves in a favourable way. Hence, especially in survey-research among the elderly, it is common practice to include SD-scales to correct for spurious relationships. In this article it is argued that the assumptions underlying such practice are doubtful, because SD-scores may be affected by a variety of factors but the tendency to present oneself favourably. Two such factors related to the question-answering process are discussed in more detail. Empirical support is provided that these factors may explain the relationship between the score on a SD-scale and age. It is argued that using SD-scales to correct for relationships between variables, may lead to erroneous results.