Evaluation of the Australian Wage Subsidy Special Youth ...

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5.5.3 Sample reduction by SYETP treatment group
5.5.3.1 Comparing those lost in attrition to those who remain
In the previous section it was found that fewer of those lost from the sample had taken
part in SYETP. Table 5.3 again examines the means for attrition effects, but focusing
within the SYETP treatment and comparison groups. This table once again expands on
the information provided in Table 1 of Richardson (1998) by including the t-test of
statistical significance for the difference between the mean of the remaining sample and
those lost. The small scale of the treatment group renders this an important means of
identifying statistically significant differences amongst the means. The wide difference in
the size of the comparison and treatment groups, allows the fluctuations in the
comparison group to dominate as the main source of statistical differences.
The first panel on the left of Table 5.3 shows the SYETP group, while the second panel
on the right shows the comparison group. Within each panel, the same format as that of
Table 5.2 is followed, with the mean in the remaining sample in the first column, the
standard deviation in the second column, the mean for those lost in the third column, the
standard deviation in the fourth, the absolute difference between the means in the fifth
column and the t statistic in the sixth column. Column 1 in the first panel corresponds to
Column 2 of Table 1 of Richardson (1998) p14, while Column 2 in the second panel
reflects the same information as Column 3 of Table 1 of Richardson (1998). Generally,
all statistics are in agreement, which is seen as a further check that the same final sample
as Richardson (1998) has been achieved.
The SYETP treatment group shows an important difference on two key characteristics,
the proportion of time spent unemployed in the 1984 reference period, and the share with
year 12 schooling. Those lost had a much smaller proportion of their time spent
unemployed, almost half of that for those remaining in the sample. In addition, far fewer
had the year 12 leaving certificate than those left in the sample.