| Completions
Undergraduate academic outcomes
for 1992 commencing students August 1999 Occasional Paper Series Higher Education Division |
Logistic regression analysis requires that where an independent variable has more than two values a control group is required. In practice this means that one category of a variable must be excluded from the regression analysis. The results for the remaining variable values are assessed against this control value. For example for the mode of study, studying externally was the control group. The control groups for other variables are at Appendix B. A control group was not necessary in the case of age because age is used as a continuous variable.
The pattern of completion for men and women is very different. On this basis they are treated as two separate groups and separate logistic models were used to estimate the probability of completion. This also avoids the assumption that all variables have the same impact by gender.
A priori, individuals who go to university straight from secondary school have different characteristics than other people. On this basis students with a Tertiary Entrance Rank (TER) and without a TER were again treated as two different populations. This also avoids the problem associated with missing values in a logistic regression.
It is appropriate to use logistic regression to analyse the dependent variable when the dependent variable can be characterised as a dichotomous variable. Specifically it is assumed that
(1)
where
y is the dependent variable; and
xi are the independent variables.
In addition to the full models, reduced models were derived using a likelihood ratio elimination test on sets of characteristics. The likelihood ratio test eliminated one characteristic at a time followed by an estimation of the model by observing the change in the log likelihood. The resulting models were parsimonious versions of the full models.
Crude completion rates were calculated using a cross-tabular analysis. The results are displayed in Tables B1a and B1b. The same population was used for the cross-tabular analysis as for the logistic regression analysis. The models were simplified where appropriate. The adjusted completion rates are calculated from the models as in B2a and B2b. In order to compare results across gender the weights of the average person with TER and without TER are used to determine the probabilities of completion.
Table B1a Completion rates for certain characteristics (TER score)
Females |
Males |
|||
| Variables | Crude |
Adjusted |
Crude |
Adjusted |
| Student cohort population | 71.9 |
71.9 |
64.5 |
66.4 |
| Language background | ||||
| Non-English speaking background | 76.4 |
76.2 |
69.5 |
70.8 |
| English speaking background | 71.2 |
71.1 |
63.6 |
65.6 |
| Aboriginal or Torres Strait Islander | ||||
| ATSI background | 45.7 |
49.4 |
30.8 |
34.1 |
| Non-ATSI background | 71.9 |
72.0 |
64.5 |
66.5 |
| Mode of study | ||||
| Full-time | 73.4 |
73.2 |
66.0 |
67.6 |
| Part-time | 45.7 |
47.9 |
40.6 |
43.7 |
| External | 19.9 |
26.6 |
19.9 |
32.4 |
| Field of study | ||||
| Agriculture, Animal husbandry | 71.1 |
75.3 |
62.4 |
71.8 |
| Architecture, Building | 78.6 |
73.9 |
68.5 |
67.1 |
| Arts, Humanities and Social sciences | 66.9 |
68.1 |
59.2 |
63.3 |
| Business, Admin., Economics | 73.6 |
73.4 |
68.4 |
68.6 |
| Education | 72.4 |
76.0 |
60.4 |
70.0 |
| Engineering, Surveying | 73.5 |
68.0 |
64.2 |
60.0 |
| Health (except Nursing) | 87.3 |
82.2 |
87.9 |
76.0 |
| Health—Nursing | 75.7 |
82.0 |
61.4 |
75.6 |
| Law, Legal studies | 80.6 |
72.8 |
80.4 |
67.0 |
| Science | 70.0 |
68.9 |
59.9 |
62.9 |
| Veterinary science | 90.5 |
84.0 |
88.6 |
81.0 |
| Region | ||||
| Urban | 72.2 |
71.7 |
65.1 |
66.4 |
| Rural | 71.3 |
73.0 |
62.1 |
66.4 |
| Isolated | 64.7 |
66.7 |
58.6 |
66.4 |
| Socio-economic background | ||||
| Most disadvantaged | 70.9 |
71.9 |
61.6 |
66.4 |
| More disadvantaged | 71.4 |
71.9 |
62.3 |
66.4 |
| More advantaged | 71.3 |
71.9 |
65.9 |
66.4 |
| Most advantaged | 73.9 |
71.9 |
67.9 |
66.4 |
| Age | ||||
| 17 | 74.5 |
73.3 |
69.5 |
69.8 |
| 18 | 72.6 |
71.9 |
64.3 |
66.4 |
| 19 | 67.5 |
70.6 |
57.3 |
63.6 |
| 20–24 | 59.3 |
67.4 |
50.2 |
58.5 |
| TER | ||||
| 1st decile | 85.8 |
84.6 |
88.6 |
87.6 |
| 2nd decile | 80.4 |
80.4 |
80.6 |
80.7 |
| 3rd decile | 78.6 |
78.6 |
76.5 |
76.6 |
| 4th decile | 75.5 |
76.0 |
70.0 |
70.1 |
| 5th decile | 72.0 |
72.8 |
65.3 |
66.0 |
| 6th decile | 69.4 |
69.4 |
59.7 |
60.2 |
| 7th decile | 67.5 |
66.6 |
57.5 |
58.6 |
| 8th decile | 64.0 |
63.2 |
52.9 |
53.6 |
| 9th decile | 64.1 |
62.3 |
47.5 |
48.4 |
| 10th decile | 61.4 |
57.2 |
46.0 |
47.1 |
Table B1b Completion rates for certain characteristics (no TER score)
Females |
Males |
|||
| Variables | Crude |
Adjusted |
Crude |
Adjusted |
| Student cohort population | 64.2 |
60.6 |
55.5 |
58.3 |
| Language background | ||||
| Non-English speaking background | 66.2 |
62.9 |
56.3 |
58.3 |
| English speaking background | 63.9 |
60.3 |
55.4 |
58.3 |
| Aboriginal or Torres
Strait Islander |
||||
| ATSI background | 38.4 |
35.9 |
25.1 |
25.9 |
| Non-ATSI background | 64.7 |
61.0 |
56.1 |
58.9 |
| Mode of study | ||||
| Full-time | 72.3 |
69.5 |
64.7 |
68.6 |
| Part-time | 56.4 |
50.5 |
45.8 |
47.5 |
| External | 48.6 |
40.4 |
32.9 |
34.8 |
| Field of study | ||||
| Agriculture, Animal husbandry | 55.7 |
55.2 |
49.7 |
53.7 |
| Architecture, Building | 70.4 |
61.4 |
58.9 |
56.0 |
| Arts, humanities and social sciences | 54.7 |
52.2 |
53.3 |
53.0 |
| Business, Admin., Economics | 53.8 |
52.3 |
50.0 |
51.9 |
| Education | 73.8 |
74.7 |
68.5 |
70.7 |
| Engineering, surveying | 63.9 |
52.4 |
54.7 |
50.8 |
| Health (except Nursing) | 76.5 |
72.0 |
74.3 |
71.6 |
| Health—Nursing | 75.1 |
75.2 |
66.4 |
66.9 |
| Law, Legal studies | 65.3 |
60.9 |
61.1 |
62.7 |
| Science | 57.1 |
51.1 |
51.4 |
48.2 |
| Veterinary science | 95.7 |
93.4 |
94.4 |
92.1 |
| Region | ||||
| Urban | 64.7 |
60.2 |
56.7 |
58.3 |
| Rural | 64.0 |
62.6 |
52.8 |
58.3 |
| Isolated | 51.3 |
53.0 |
43.7 |
58.3 |
| Socio-economic background | ||||
| Most disadvantaged | 61.9 |
58.7 |
52.6 |
56.8 |
| More disadvantaged | 64.0 |
60.3 |
53.5 |
57.1 |
| More advantaged | 64.1 |
60.5 |
56.7 |
59.1 |
| Most advantaged | 66.6 |
62.8 |
59.3 |
60.1 |
| Age | ||||
| 17 | 72.6 |
66.1 |
65.1 |
58.3 |
| 18 | 72.1 |
65.2 |
63.0 |
58.3 |
| 19 | 70.6 |
64.4 |
63.1 |
58.3 |
| 20–24 | 65.5 |
62.4 |
56.7 |
58.3 |
| 25–29 | 56.6 |
60.3 |
49.8 |
58.3 |
| 30–39 | 58.3 |
59.3 |
48.4 |
58.3 |
| 40–49 | 60.1 |
60.4 |
46.3 |
58.3 |
| 50 and over | 52.6 |
61.5 |
43.3 |
58.3 |
| Basis for admission | ||||
| Higher education experience | 68.0 |
66.2 |
60.7 |
63.6 |
| TAFE experience | 53.1 |
53.7 |
49.5 |
58.2 |
| Finished secondary education | 68.5 |
58.0 |
59.5 |
57.0 |
| Special entry | 54.7 |
53.4 |
45.9 |
49.4 |
| Examination | 65.4 |
58.1 |
56.9 |
52.3 |
| Professional qualification/ employment exp |
67.0 |
66.6 |
48.1 |
62.4 |
| Other basis | 60.1 |
57.3 |
48.8 |
55.2 |
Table B2a Binomial logit estimates of completion (TER)
| Regressors | Females |
Males |
||
| Constant | 2.385 |
(4.41) |
10.682 |
(7.31) |
| Language background | ||||
| Non-English speaking background | 0.262 |
(6.02) |
0.241 |
(5.42) |
| Aboriginal or Torres Strait Islander | ||||
| ATSI background | -0.966 |
(4.10) |
-1.344 |
(3.62) |
| Mode of study | ||||
| Full-time | 2.019 |
(10.87) |
1.473 |
(8.04) |
| Part-time | 0.933 |
(4.87) |
0.483 |
(2.52) |
| Field of study | ||||
| Agriculture, Animal husbandry | 0.158 |
(1.17) |
0.149 |
(1.44) |
| Architecture, Building | 0.089 |
(0.69) |
-0.073 |
(0.70) |
| Arts, Human. and Social sciences | -0.198 |
(4.66) |
-0.237 |
(4.73) |
| Education | 0.201 |
(3.77) |
0.064 |
(0.91) |
| Engineering, Surveying | -0.201 |
(2.22) |
-0.380 |
(7.92) |
| Health (except Nursing) | 0.574 |
(6.31) |
0.367 |
(3.07) |
| Health—Nursing | 0.564 |
(8.98) |
0.349 |
(3.09) |
| Law, Legal studies | 0.029 |
(0.22) |
-0.075 |
(0.55) |
| Science | -0.160 |
(3.36) |
-0.255 |
(5.67) |
| Veterinary science | 0.702 |
(1.85) |
0.668 |
(1.35) |
| Region | ||||
| Rural | 0.061 |
(1.69) |
||
| Isolated | -0.236 |
(2.30) |
||
| Socio-economic background | ||||
| Most disadvantaged | ||||
| More disadvantaged | ||||
| More advantaged | ||||
| Age | ||||
| Age | -0.242 |
(5.01) |
-1.111 |
(6.33) |
| Age squared | 0.006 |
(4.37) |
0.038 |
(5.67) |
| Age cubed | -0.00004 |
(3.35) |
-0.0004 |
(5.04) |
| 2nd decile | -0.293 |
(3.90) |
-0.528 |
(5.85) |
| 3rd decile | -0.401 |
(5.35) |
-0.774 |
(8.68) |
| 4th decile | -0.553 |
(7.50) |
-1.109 |
(12.75) |
| 5th decile | -0.718 |
(9.83) |
-1.294 |
(14.93) |
| 6th decile | -0.887 |
(12.24) |
-1.544 |
(17.94) |
| 7th decile | -1.012 |
(14.01) |
-1.614 |
(18.77) |
| 8th decile | -1.164 |
(16.16) |
-1.815 |
(21.18) |
| 9th decile | -1.204 |
(16.52) |
-2.022 |
(23.38) |
| 10th decile | -1.413 |
(19.04) |
-2.075 |
(23.60) |
Table B2b Binomial logit estimates of completion (No TER)
| Regressors | Females |
Males |
||
| Constant | 0.725 |
(3.36) |
-0.913 |
(15.46) |
| Language Background | ||||
| Non-English speaking | 0.111 |
(2.92) |
||
| Aboriginal or Torres Strait Islander | ||||
| ATSI background | -1.031 |
(12.60) |
-1.412 |
(12.89) |
| Mode of study | ||||
| Full-time | 1.214 |
(33.76) |
1.410 |
(36.46) |
| Part-time | 0.407 |
(11.61) |
0.527 |
(12.32) |
| Field of study | ||||
| Agriculture, Animal husbandry | 0.117 |
(1.13) |
0.074 |
(0.95) |
| Architecture, Building | 0.370 |
(3.51) |
0.164 |
(2.14) |
| Arts, Human. And Social Sci. | -0.003 |
(0.08) |
0.046 |
(1.16) |
| Education | 0.991 |
(24.03) |
0.806 |
(15.33) |
| Engineering, Surveying | 0.005 |
(0.05) |
-0.046 |
(0.96) |
| Health (except Nursing) | 0.853 |
(13.96) |
0.849 |
(10.53) |
| Health—Nursing | 1.015 |
(22.80) |
0.630 |
(8.40) |
| Law, Legal studies | 0.352 |
(4.58) |
0.442 |
(6.78) |
| Science | -0.049 |
(1.03) |
-0.148 |
(3.75) |
| Veterinary science | 2.560 |
(5.52) |
2.368 |
(4.58) |
| Rural | 0.099 |
(8.55) |
||
| Isolated | -0.297 |
(2.35) |
||
| Socio-economic background | ||||
| Most disadvantaged | -0.174 |
(5.09) |
-0.137 |
(3.75) |
| More disadvantaged | -0.106 |
(3.07) |
-0.123 |
(3.37) |
| More advantaged | -0.101 |
(3.13) |
-0.043 |
(1.17) |
| Age | ||||
| Age | -0.114 |
(6.83) |
||
| Age squared | 0.003 |
(6.79) |
||
| Age cubed | -0.00002 |
(6.51) |
||
| Basis for admission | ||||
| Higher education experience | 0.376 |
(8.55) |
0.350 |
(7.73) |
| TAFE experience | -0.148 |
(2.35) |
0.123 |
(1.94) |
| Finished secondary education | 0.027 |
(0.56) |
0.074 |
(1.51) |
| Special entry | -0.160 |
(3.36) |
-0.232 |
(4.58) |
| Examination | 0.033 |
(0.47) |
-0.114 |
(1.39) |
| Prof quals/employment exp | 0.396 |
(5.81) |
0.297 |
(3.21) |
Table B3 Weights for TER and no TER score
| Characteristics of average person | TER |
No TER score |
| Constant | 1.0000 |
1.0000 |
| Language background | ||
| Non-English speaking background | 0.1436 |
0.1139 |
| Aboriginal or Torres Strait Islander | ||
| ATSI background | 0.0025 |
0.0186 |
| Mode of study | ||
| Full-time | 0.9487 |
0.5954 |
| Part-time | 0.0427 |
0.2342 |
| Field of study | ||
| Agriculture, Animal husbandry | 0.0162 |
0.0198 |
| Architecture, Building | 0.0192 |
0.0208 |
| Arts, Humanities and Social sciences | 0.2383 |
0.2572 |
| Education | 0.0971 |
0.1609 |
| Engineering, Surveying | 0.1013 |
0.0499 |
| Health (except Nursing) | 0.0454 |
0.0473 |
| Health—Nursing | 0.0594 |
0.1135 |
| Law, Legal studies | 0.0184 |
0.0344 |
| Science | 0.2043 |
0.1277 |
| Veterinary science | 0.0026 |
0.0028 |
| Region | ||
| Rural | 0.1955 |
0.2282 |
| Isolated | 0.0162 |
0.0275 |
| Socio-economic background | ||
| Most disadvantaged | 0.2500 |
0.2500 |
| More disadvantaged | 0.2500 |
0.2500 |
| More advantaged | 0.2500 |
0.2500 |
| Age | ||
| Age | 18 |
26 |
| Age squared | 324 |
676 |
| Age cubed | 5832 |
17576 |
| TER | ||
| 2nd decile | 0.1000 |
|
| 3rd decile | 0.1000 |
|
| 4th decile | 0.1000 |
|
| 5th decile | 0.1001 |
|
| 6th decile | 0.1000 |
|
| 7th decile | 0.1000 |
|
| 8th decile | 0.1001 |
|
| 9th decile | 0.1000 |
|
| 10th decile | 0.0998 |
|
| Basis for admission | ||
| Higher education experience | 0.3957 |
|
| TAFE experience | 0.0571 |
|
| Finished secondary education | 0.2066 |
|
| Special entry | 0.1778 |
|
| Examination | 0.0357 |
|
| Professional qualif./employ. exp | 0.0392 |