The size of the cohort of families participating in
the Newpin program influences the number of
restorations achieved by the program but not the
Restoration Rate. The Restoration Rate is however
impacted by the potential for statistical error
associated with small sample sizes. The smaller
the intervention group the larger the potential
error band. Investors are shielded from cohort
size risks, including variability in the number of
Newpin centres operating, the average time a family
spends in the Newpin program, and the proportion
of centre places occupied by Cohort 1 families. In
addition, the use of a cumulative Restoration Rate
will reduce the statistical error associated with small
sample sizes over time.