The study suggests that this impact works partly through improved sanitation, partly through improved nutritional status, and partly through reduction in psychosocial stress. Case (2001b) - based on the same dataset - finds that the presence of a pensioner is associated with an increase of about five centimetres of children's height for age after controlling for a range of household and individual factors. This is equivalent to about half a year’s growth for children aged zero to six. Her study uses the 1993 PSLSD data, and focuses on children aged 6-60 months.