The article discusses the problem of missing data in survey research self-report data. The author states that many times it is assumed that the missing data has been minimized in the data collection phase of research to the extent possible, and that some "adjustment" to the data set has been made to account for it. The article says that how to assign missing data depends on the actual distribution of missing responses, the relationships between those missing values, and other variables of interest. Data could be missing because of participants not responding to certain questions and other times it is missing at random. Several methods for solving the problem are presented including Listwise deletion, pairwise deletion, and mean substitution.