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Delving Deeper into the Graduate Experience. David Carroll, Research Associate. Introduction. National survey of higher education graduates conducted since 1972 Current iteration is known as the Australian Graduate Survey (AGS) Comprises: Graduate Destinations Survey (GDS)
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Delving Deeper intothe Graduate Experience David Carroll, Research Associate
Introduction • National survey of higher education graduates conducted since 1972 • Current iteration is known as the Australian Graduate Survey (AGS) • Comprises: • Graduate Destinations Survey (GDS) • Course Experience Questionnaire (CEQ) or Postgraduate Research Experience Questionnaire (PREQ)
Graduates surveyed approximately four months after the completion of their studies • Total of 119,447 responses received in 2008 (56.4 per cent response rate) • Key findings disseminated through a series of annual research reports produced by GCA
Graduate Destinations • Examination of work and study activities of new graduates • Current AGS and time series • Compares relative proportions of graduates in discrete categories (e.g. % in FTE vs. % seeking FTE) • Postgraduate Destinations report also produced
Graduate Salaries • Examination of earnings of recent higher education graduates • Current AGS and time series • Median starting salaries of bachelor degree graduates, along with comparative salary figures from other groups
Scope for Additional Analyses • Widely used for strategic decision making • Reports focus on descriptive statistics • Diverse readership meant keeping reports as ‘accessible’ as possible • Concern that additional analyses would limit their use as communication tools
The Challenge: • How best to incorporate new analyses into these reports to complement and enhance the analyses contained within… • Without reducing their usefulness as non-technical communication tools • Graduate Salaries 2008 selected as a test case for the addition of new analyses • Do they provide additional value? • Possible within already tight timelines?
Three criteria for new analyses: • Methodologically appropriate • Complement and enhance • Easily understood and interpreted • Adjustment for Inflation • Statistical Significance Testing
Adjustment for Inflation • Inflation refers to the sustained increase in the overall price level in an economy • Inflation is caused by: • Growth in the money supply (long term) • Supply and demand pressures (short term) • Important to consider impact of inflation when examining values of money over time
Necessary to consider the real value of median starting salary to understand the practical implications for graduates. • Calculated based on annual percentage change in the Consumer Price Index (CPI) Dollars base = Dollars data (Annual CPI base / Annual CPI data)
This approach was chosen because: • Familiar concept • Widely accepted methodology • Publicly available indices
Inferential Statistics • Emphasis in these reports placed on differences between groups of interest • Descriptive statistics (of AGS sample) • Can between group differences be inferred to exist in the overall graduate population? • Significance tests incorporated into Graduate Salaries 2008 to address this question
Challenges: • Non-normal distribution confirmed by graphical and statistical examination • Selected tests needed to fit within existing report structure to ensure continuity • Results (and their interpretation) needed to be meaningful to a wide audience
Non-Parametric Tests • Mann-Whitney U (Wilcoxon Rank-Sum) • Kruskal-Wallis • Differences flagged as: • Significant at the 5 per cent level (*) • Significant at the 1 per cent level (**) • Not statistically significant (n.s.) • All p-values provided in an appendix
Results of these tests discussed in the report in practical terms: The largest difference in median salary by gender was in the field of optometry ($8,000), which was statistically significant at the 5 per cent level. This basically means that there is less than a one-in-twenty chance that this gender difference does not occur in the overall graduate population. (Adapted from Graduate Salaries 2008)
Explanation of Concepts • Statistical significance • vs. practical significance
Differences by Gender (2) † Female median GSS larger than male median GSS.
Differences by Industry † Aust. Govt, State Govt, Public Health, Prof. Pract. Ind./Com., Schools, Tert. Ed.
† Aust. Govt, State Govt, Public Health, Prof. Pract. Ind./Com., Schools, Tert. Ed.
Differences Between Proportions • Graduate Destinations focus on relative proportions of graduates within categories • Two proportion z-test proposed to examine two subgroups of interest: • Proportion of graduates engaged in particular activities • Proportion engaged in particular activities in different years
Multiple Comparisons • Kruskal-Wallis Test indicates that at least one pair of groups are different • No multiple comparison tests for Kruskal-Wallis included in Graduate Salaries 2008 • Recommended that readers compare medians to identify extreme groups (after Dytham, 2003) • Considering adding multiple comparison tests in Graduate Salaries 2009
Dunn’s Test • Multiple comparison procedure for Kruskal-Wallis when sample sizes are not equal • Minimises Type I errors (falsely rejecting H0) when performing multiple pairwise comparisons (Q statistic)
Differences by Industry † Aust. Govt, State Govt, Public Health, Prof. Pract. Ind./Com., Schools, Tert. Ed.
Differences by Industry † Aust. Govt, State Govt, Public Health, Prof. Pract. Ind./Com., Schools, Tert. Ed.
Humanities Graduates QCrit = 3.038 (p < .05; k = 7)
Humanities Graduates QCrit = 3.038 (p < .05; k = 7)
Conclusions • Inflation adjustment permits salaries over time to be examined on a common base • Practical implications for graduates • Statistical significance tests allow for more reliable inferences to the overall population • Even more robust and comprehensive understanding of graduate outcomes
Questions? David Carroll Graduate Careers Australia research@graduatecareers.com.au +61 3 9605 3700 www.graduatecareers.com.au