Intensity

The intensity o f the intervention has been found in several studies to affect the success o f the intervention. A study in Jamaica investigated the effectiveness o f differing intensities o f a home visiting intervention (Powell & Grantham-McGregor). The intervention involved home visits for 2 years by paraprofessionals in which home made toys and books were brought to the home and the caregivers shown age appropriate activities to do with their child. Children receiving weekly visits were compared with those receiving fortnightly and monthly visits and a non-visited control group. The gains in child development were found to increase with increased frequency o f visiting (Figure

1.9).

Figure 1.9. Effects of Different Visiting Frequency on Child DQ in Jamaica

DQ 110 1 weekly

106 -

Powell & Grantham-McGregor, 1989

Increased duration o f intervention also resulted in increased cognitive gains in the com bined health, nutrition and stim ulation study in Cali with (M cK ay et al, 1979) - see Figure 1.2.

A dose-response effect o f treatm ent on parenting outcom es w as reported by Olds et al (1986) in a nurse hom e visiting program . W om en were random ized to receive prenatal visits only, pre and post-natal visits and a control group. The group receiving pre and post natal visits scored higher than the group receiving prenatal visits only who in turn scored higher than the controls on two subscales o f the HOM E.

Ram ey et al (1992) devised a ‘fam ily participation index’ by sum m ing the num ber o f days each child spent in the centre, the num ber o f com pleted hom e visits and the num ber o f parent m eetings attended. The index was positively related to child cognition in a dose response m anner (Figure 1.10.). Com parable levels o f participation w ere found for m others o f different ethnicity, education and for children o f different birth weights, gender and neonatal health status as well as across 8 geographical sites. How ever, it is still possible that some unm easured factor covaried with both participation and child IQ.

Figure 1.10. Degree of participation in IHDP and intellectual functioning at age 3

% IQ ^ 7 0

Control Low M edium High

participation participation participation

R am ey at al, 1992

There is some evidence that the effect of the intensity varies as a function o f the characteristics o f the participants. For example, in a study with mothers o f preterm infants, a one hour session promoting maternal sensitivity and responsiveness was sufficient to produce significant benefits to maternal interaction at 5 months for well- educated mothers (Kang et al, 1995). However, for mothers with lower levels of education an additional follow on intervention o f home visiting was required for significant differences to be evident.

A relationship between degree o f participation and child and/or maternal outcomes has not been found in all programs which have undertaken this analysis. For example, in the Comprehensive Child Development Program (St Pierre & Layzer, 1999) no statistically or educationally significant differences were found for families with high levels of participation. However, in the latter study as there were no benefits for the sample as a whole, it could be that the quality o f the program was insufficient.

1.10.2. Quality

We would expect that the quality o f the program would be an important factor influencing outcomes and yet few projects have examined this issue.

In Columbia, ‘Homes o f Well-Being’ are supported in which community mothers (paraprofessionals) look after up to 15 children aged 2 to 5 years. Children are fed, their growth is monitored and educational activities are conducted. An evaluation o f the programme was conducted in which influences on children’s development were examined using multi-variate analysis (WHO, 1999). No relationship was found between duration o f time in the program and the risk status o f the children. There was however a small, but significant association (r = .17) between program quality and child well-being in terms o f nutrition, health and psychosocial development. In addition, the proportion o f children with a developmental delay was lower in homes run by the more experienced community mothers. These results suggest that the quality o f the programme was more important in predicting child development than the quantity of exposure the child received.

The Victoria Day Care Research Project in Canada found that the quality o f child care was highly predictive o f child language development and this was particularly important for children o f low SES (Goelman & Pence, 1987).

In the multi-site Comprehensive Child Development Program gains for the intervention group were found for child IQ, mother’s parenting attitudes and the number o f mothers in paid employment in one site only (St. Pierre & Layzer, 1999). The authors attributed this success to factors reflecting program quality including a clear focus on child education, low turnover o f senior staff and support at the state level.