Figure 5.2 shows the variation in core unplanned and gross turnover rates for individual departments. Higher gross turnover can indicate an above average use of fixed-term staff or significant change programmes within an organisation.
Figure 5.2 Gross and core unplanned staff turnover by department, June year 2015
Turnover tends to be higher for small departments. This relationship is also seen in the private sector9. There are a number of potential reasons for this. There are often fewer opportunities for advancement within smaller organisations so employees need to move to gain experience or to advance their careers. Also, turnover rates are more volatile in smaller organisations. For example, one person leaving in an organisation of only 30 people will increase the turnover rate by over three percentage points.
Note in Figure 5.2, the large difference between gross and unplanned turnover for the Department of Conservation, CERA and the Ministry of Pacific Island Affairs is due to the relatively high number of fixed-term contracts coming to an end during the year. In particular, all staff at CERA are on fixed-term contracts, therefore by definition CERA cannot have any unplanned turnover.
 As shown by Statistics New Zealand's Linked Employer-Employee Dataset (LEED) worker turnover statistics.