Evaluation of the Australian Wage Subsidy Special Youth ...
Evaluation of the Australian Wage Subsidy Special Youth ... Evaluation of the Australian Wage Subsidy Special Youth ...
150 indicated that even significant attrition which is observed to be selective in nature does not introduce strong biases in estimation results. Falaris and Peters (1998) p 531 noted that effects of attrition on regression estimates in general is negligible, or only affects the intercept. The overarching message from these studies is that attrition bias, even when found to act selectively on observable characteristics, does not necessarily bias the estimates of interest in modelling. Other evidence also points to the importance of validating the extent of attrition bias effects on the estimates of interest. Alderman et al. (2000) apply the methods set out in Fitzgerald et al. (1998a), and find some outcomes are affected by attrition bias while others are not. They find that univariate comparisons showing systematic attrition affecting particular variables of interest do not translate to these variables being significant in a probit model predicting attrition. They warn that in the relations they modelled attrition bias led to striking differences affecting the coefficients for some models of outcomes but not others. They further point out that their results indicate that attrition bias conclusions are not generalisable to all multivariate estimates or all data, but that the particular model, outcome of interest and data need to be assessed. 5.4 Empirical attrition test and treatment Fitzgerald et al. (1998b) examined the Michigan Panel Study on Income Dynamics (PSID) of the US, and found attrition was highly selective, concentrated amongst those of lower socioeconomic status. Usefully, they outlined the statistical framework for tests for attrition bias within an econometric context. In their model, a key distinction is drawn between attrition where selection is on observables as opposed to selection upon unobservables. The background for their approach is the selection bias modelling econometric literature, deriving chiefly from Heckman (1979). The earlier attrition study of the PSID by Becketti et al. (1988) is shown to be a close relative of the direct modelling of attrition proposed by Fitzgerald et al. (1998a). Their model is defined as follows: (9) Y = β 0 + β 1 X + ε
151 (10) A* = δ 0 + δ 1 x +δ 2 z + ν (11) A =1 if A* ≥ 0 and A=0 if A*
- Page 115 and 116: 99 suitability of the underlying as
- Page 117 and 118: 101 Heckman, Lalonde and Smith (199
- Page 119 and 120: 103 effect on employment relative t
- Page 121 and 122: 105 Table 3.1, Part A Employment eq
- Page 123 and 124: 107 (-1.80) (-1.80) Tradesperson -0
- Page 125 and 126: 109 duration of Pre-June 1984 unemp
- Page 127 and 128: 111 4: Study 2 Propensity score mat
- Page 129 and 130: 113 Propensity score matching provi
- Page 131 and 132: 115 4.2 Propensity score matching m
- Page 133 and 134: 117 covariates that influence the a
- Page 135 and 136: 119 (7) E(Y c | D=1) = E P(X) {E[Y
- Page 137 and 138: 121 For CIA to be plausible, a ‘r
- Page 139 and 140: 123 employment and programme partic
- Page 141 and 142: Highest qualification in 1984 (1.56
- Page 143 and 144: 127 4.6 Distribution of the propens
- Page 145 and 146: 129 Figure 4.3 Histograms of estima
- Page 147 and 148: 131 Table 4.5 Summary statistics fo
- Page 149 and 150: 133 Table 4.5, that the variance of
- Page 151 and 152: 135 Table 4.6 Matching results, Sin
- Page 153 and 154: 137 Table 6.3 using Swedish data wi
- Page 155 and 156: 139 matching is the ability to weed
- Page 157 and 158: 141 Table 4.7 Matching results, All
- Page 159 and 160: 143 the unobserved component. If th
- Page 161 and 162: 145 5: Study 3 Attrition and non-re
- Page 163 and 164: 147 occur by design, because the mi
- Page 165: 149 (1990) extended and improved th
- Page 169 and 170: 153 again from September to Novembe
- Page 171 and 172: 155 5.5.2 Univariate examination of
- Page 173 and 174: 157 lower, the job lengths are only
- Page 175 and 176: 159 Work limited by health 1984 0.1
- Page 177 and 178: 161 The characteristics of the SYET
- Page 179 and 180: 163 para-professional Mother not em
- Page 181 and 182: 165 comparison group where the shar
- Page 183 and 184: 167 5.5.4 Attrition: natural attrit
- Page 185 and 186: 169 both sources that impose change
- Page 187 and 188: 171 para-professional Father not em
- Page 189 and 190: 173 work in later sections, this su
- Page 191 and 192: 175 Table 5.6: Effect of selection/
- Page 193 and 194: 177 appropriate to discard these fr
- Page 195 and 196: 179 Australia/Tasmania. Amongst tho
- Page 197 and 198: 181 Table 5.5a Summary statistics b
- Page 199 and 200: 183 5.6.1.2 Effects of the non-resp
- Page 201 and 202: 185 3 years + -0.35 -0.47 -0.34 -0.
- Page 203 and 204: 187 5.7 Multivariate analysis of ef
- Page 205 and 206: 189 proportion of time spent unempl
- Page 207 and 208: 191 post-school qualification, and
- Page 209 and 210: 193 Generally, those variables foun
- Page 211 and 212: 195 longj0 Longest job by 1984 < 1
- Page 213 and 214: 197 adopted in order to maintain co
- Page 215 and 216: 199 6: Study 4 Weighting to counter
151<br />
(10) A* = δ 0 + δ 1 x +δ 2 z + ν<br />
(11) A =1 if A* ≥ 0 and A=0 if A*