He further points out that “the spurious precision of quantified staffing level plans has little value when reconciled with the complex and frequently changing nature of man power, the business and the external environment”. The concept of Human Resource Planning (HRP) fails because the ability to make these estimates must be severely limited by the definitely predicting the influence of external events. “There is a risk that sensible anticipation gets converted into foolish numbers and their validity depends on large, loose assumptions”, according to Heller (1972).