THE ECONOMICS OF SKILLS MISMATCH IN GRADUATE UNEMPLOYMENT

Background to the Study

Conventional Mincer earnings function log earnings = β0 + β1 schooling + β2 experience + β3 experience² + ε estimates single return to schooling assuming all years equally valued regardless of job requirement. ORU extension decomposes attained schooling S = R + O - U where R required education years O surplus overeducation years if S>R else 0 U deficit undereducation years if R>S else 0. Wage equation log w = α + βr R + βo O + βu U + controls + ε. Classic finding across countries βr > βo >0 > βu? Actually literature typically βr positive largest βo positive but smaller than βr βu negative indicating penalty for deficit. This ranking implies overeducated workers earn more than matched workers in same required-level job but less than they would if matched at own attained level.

Nigerian graduate market with expansion of tertiary education without commensurate growth of graduate-level jobs creates conditions for high overeducation incidence 38.2 percent in this sample consistent with continental 8.3 percent overeducation but higher due to graduate-only sample versus youth overall. Undereducation 39.2 percent also high reflecting polytechnic graduates in jobs requiring higher qualifications perhaps due to experience substituting for formal education. Self-report worker self-assessment method asks worker what minimum education required for job widely used but imperfect relative to job-analysis external occupation classification.

For foundational earnings theory see NBER Mincer earnings function review and African mismatch evidence AfDB education and jobs mismatch paper and ILO skills mismatch measurement. Related graduate employment frameworks in labour economics project topics on SCHOLARNESTHUB.

Statement of the Problem

Existing Nigerian research on graduate skills mismatch predominantly documented incidence and qualitative consequences difficulty filling available jobs employer preference for foreign-trained graduates perceived disconnect between university curricula and labour-market skill requirements rather than formally decomposing and quantifying specific wage consequences using Duncan-Hoffman ORU econometric framework that has become standard approach in broader international and African mismatch literature Morsy & Mukasa 2019 Herrera & Merceron 2013. This meaningful gap: without ORU decomposition not possible to distinguish whether Nigerian graduates who are mismatched nonetheless earn positive return on surplus schooling consistent with classic finding that overeducated workers still out-earn matched workers with same required-level job even if earn less than they would in matching graduate-level job or whether labour market sufficiently dysfunctional surplus schooling earns no return. Similarly without separately estimating required-education and undereducation-deficit coefficients not possible to test whether employers penalise underqualified workers in specific quantifiable way ORU framework predicts. This study addresses gap using primary Nigerian graduate labour-market survey data and full ORU wage regression.

Aim and Objectives of the Study

Aim is to examine economics of skills mismatch in Nigerian graduate employment using Duncan-Hoffman 1981 Overeducation-Required-Undereducation earnings-decomposition framework.

·         Determine incidence of vertical educational mismatch overeducation undereducation adequate matching among employed Nigerian graduates;

·         Estimate separate wage returns to required education surplus overeducation years and deficit undereducation years using Duncan-Hoffman ORU wage model;

·         Formally test whether wage return to required education differs significantly from return to surplus overeducation years;

·         Compare explanatory power of ORU model against conventional Mincer earnings model that does not account for mismatch; and

·         Draw policy-relevant conclusions on economic cost of graduate skills mismatch in Nigeria.

Research Questions

·         What proportion of employed Nigerian graduates are overeducated undereducated or adequately matched relative to current job educational requirements?

·         What is wage return to required education surplus overeducation years and deficit undereducation years respectively?

·         Does wage return to required education differ significantly from return to overeducation years?

·         Does ORU model explain graduate wage variation significantly better than conventional Mincer model that ignores mismatch?

Research Hypotheses

H01: Required education overeducation years and undereducation years have no statistically significant effect on graduate wages.
H02: Wage return to required education does not differ significantly from wage return to overeducation years.
H03: Field of study STEM versus non-STEM and sector of employment have no statistically significant effect on graduate wages independent of educational mismatch.
Tested at 5 percent significance level.

Significance of the Study

To National Universities Commission and Federal Ministry of Education providing quantified evidence on wage cost of graduate skills mismatch directly relevant to ongoing curriculum-reform and university-industry-linkage policy discussions showing ORU explains R2 0.435 versus Mincer 0.389 and return to required 9.2 percent versus overeducation 6.7 percent with penalty for undereducation −3.7 percent. For National Directorate of Employment and graduate-employability programming study decomposition identifies how much problem operates through outright joblessness versus employed-but-mismatched underemployment informing intervention design. For employers and HR practitioners offers evidence on wage-setting implications of hiring decisions placing graduates below or above nominal qualification level. For academic literature extends AfDB continental mismatch-incidence evidence Morsy & Mukasa 2019 and descriptive Nigerian mismatch literature with formal ORU wage-decomposition specific to Nigerian graduate labour market. Further applications in education project topics on SCHOLARNESTHUB.

Scope of the Study

Delimited to employed Nigerian university and polytechnic graduates holding OND/HND Bachelor's Master's PhD-level qualifications currently in paid employment examining current monthly wages in relation to years education attained years education required by current job determined via job-analysis/self-report method and resulting overeducation and undereducation decomposition alongside standard human-capital and job-characteristic controls.

Limitations of the Study

·         Years of education required variable measured via graduates own assessment of job minimum educational requirement well-established but imperfect measurement approach self-report or worker self-assessment method relative to alternative job-analysis external occupation-based classification method two methods known to sometimes yield different mismatch-incidence estimates.

·         Measures vertical qualification-level mismatch specifically rather than horizontal field-of-study mismatch though inclusion of STEM/non-STEM field-of-study control partially proxies for distinct dimension.

·         Cross-sectional design captures mismatch and wages at single point and cannot speak to whether mismatch is transitional early-career phenomenon that resolves as graduates gain experience or more persistent labour-market feature distinction literature Sicherman 1991 suggests may be economically important.

·         Self-reported wage data subject to measurement error and potential under- or over-reporting.

Operational Definition of Terms

Vertical Skills Mismatch: Situation where worker attained level of education differs from level required by current job classified as overeducation attained exceeds required 38.2 percent in sample averaging 1.99 surplus years undereducation required exceeds attained 39.2 percent averaging 1.77 deficit years or adequate matching 22.5 percent.

Overeducation: Number of years by which worker attained education exceeds education required for current job significant positive return 6.7 percent per year p<0.001 but less than return to required education.

Undereducation: Number of years by which education required for worker current job exceeds attained education significant wage penalty −3.7 percent per year p 0.009.

ORU Model: Mincer-type earnings-function extension Duncan & Hoffman 1981 that decomposes attained years schooling into required surplus overeducation and deficit undereducation components each entered as separate regressor in wage equation explaining R2 0.435 versus Mincer 0.389 and Wald test p 0.047 confirms βr > βo.

Mincer Earnings Function: Standard human-capital wage equation Mincer 1974 relating logarithm of earnings to years schooling and quadratic function of labour-market experience benchmark for comparison.

Graduate Underemployment: Situation in which employed graduate works in job that does not fully utilise qualifications skills or educational attainment encompassing but not limited to formal overeducation.

Short Conclusion

Findings demonstrate vertical skills mismatch carries real asymmetric wage cost in Nigerian graduate labour market. Incidence 22.5 percent adequately matched 38.2 percent overeducated 1.99 surplus years 39.2 percent undereducated 1.77 deficit years indicates substantial mismatch. ORU model finds returns required education 9.2 percent per year p<0.001 overeducation 6.7 percent p<0.001 undereducation penalty −3.7 percent p 0.009 Wald test confirms βr > βo p 0.047 replicating classic Duncan-Hoffman ranking and explains meaningfully more variation R2 0.435 versus conventional Mincer 0.389 demonstrating practical value of fuller decomposition. Policy recommendations include curriculum reform aligning with labour-market requirements career-guidance programming to support mismatched graduates transition into better-matched roles and routine incorporation of job-requirement measures into national graduate-tracer surveys such as NUC tracer. Further guidance in graduate employability project topics on SCHOLARNESTHUB.

Frequently Asked Questions

Q: What is vertical skills mismatch and ORU model?

A: Vertical mismatch when attained education differs from required for job classified overeducation surplus or undereducation deficit; ORU model Duncan-Hoffman 1981 decomposes attained schooling into required surplus deficit components in Mincer-type wage equation to estimate separate returns.

Q: What incidence of mismatch found in Nigerian graduates?

A: 22.5 percent adequately matched 38.2 percent overeducated averaging 1.99 surplus years 39.2 percent undereducated averaging 1.77 deficit years among 400 employed OND/HND Bachelor's Master's PhD holders self-report job-requirement measure.

Q: What are wage returns to required overeducation undereducation years?

A: Required education 9.2 percent per year p<0.001 overeducation 6.7 percent p<0.001 positive but smaller undereducation penalty −3.7 percent per year p 0.009 indicating overeducated earn more than matched peers in same job but less than if matched at own level.

Q: Does ORU model outperform conventional Mincer?

A: Yes ORU R2 0.435 versus Mincer benchmark ignoring mismatch R2 0.389 demonstrating practical value of decomposition and Wald test confirms return to required significantly larger than overeducation p 0.047 replicating classic ranking.

Q: How does African continental evidence compare?

A: AfDB study across ten African countries 8.3 percent overeducated 56.9 percent undereducated 17.5 percent overskilled 28.9 percent underskilled among employed youth with overeducation penalty and undereducation premium in continental sample; Nigerian graduate sample shows higher overeducation 38.2 percent due to graduate-only focus.

Q: What measurement method was used for required education?

A: Self-reported worker self-assessment method graduates own assessment of job minimum educational requirement well-established but imperfect versus external job-analysis occupation-based classification limitation acknowledged.

Q: What policy recommendations to reduce mismatch cost?

A: Curriculum reform aligning with market needs career-guidance programming supporting mismatched graduates transition into better-matched roles routine incorporation of job-requirement measures into national graduate-tracer surveys university-industry linkages.

Q: What is difference between overeducation and graduate underemployment?

A: Overeducation specific measure surplus years formal qualification-level mismatch; graduate underemployment broader situation employed graduate works in job not fully utilising qualifications skills encompassing but not limited to overeducation.

Q: What are limitations of this study?

A: Self-report required-education measure may differ from job-analysis method measures vertical not horizontal field-of-study mismatch though STEM control partially proxies cross-sectional cannot distinguish transitional early-career versus persistent mismatch self-reported wage measurement error.

Q: Why is STEM versus non-STEM control included?

A: Field of study influences wages independent of vertical mismatch and partially proxies horizontal field-of-study mismatch dimension alongside vertical qualification-level mismatch.