Лазаров, Деян2025-02-2220101311-221-Xhttp://research.bfu.bg:4000/handle/123456789/31The paper discusses the principles of missing values (MV) patterns and mechanisms. Using Labour Force Survey conducted in Bulgaria 2007 by National Statistical Institute are evaluated the MV mechanisms among employed by permanence of job and is shown that mechanism is not MCAR. In efforts to sift the MAR and MNAR mechanisms K-means cluster procedure is used and two different groups of individuals ware found. In this two groups are implemented imputation by EM algorithm that performs very well in this situation.bgMissing ValuesMissing MechanismMissing patternLabour Force SurveyImputationEM algorithmArticle