5. Education Quality
KAT.TAL.322 Advanced Course in Labour Economics
Education quantity vs quality
Education quality
Knowledge/productivity doesn’t rise linearly with years of education.
Production process that takes inputs and develops skills.
What are relevant inputs?
What are relevant outputs?
How does production process work?
Education production function
Education production function
Simple framework
Education output of pupil \(i\) in school \(j\) in community \(k\)
\[ q_{ijk} = q(P_i, S_{ij}, C_{ik}) \]
where \(\begin{align}P_i &\quad \text{are pupil characteristics} \\ S_{ij} &\quad \text{are school inputs} \\ C_{ik} &\quad \text{are non-school inputs}\end{align}\)
Education production function
Measures
Test scores
Cognitive skill measure
Skills that are valued in the labour market
Latent ability vs measured tests
Noncognitive skills
Itself a multivariate object
Slowly finding its way to most surveys (Big 5)
Role of investments in shaping these
Early estimates of school inputs (prior to 1995)
Early estimates of school inputs
Methodological concerns
Static vs cumulative \(\Rightarrow\) levels vs value added
Endogenous allocation of resources by schools
Differences in measured output, multiple outputs
Aggregate policy inputs (curricula, regulation, institutions, etc.)
Other school inputs (selectivity, teacher biases)
Stronger results in lower quality studies
Outputs: test scores vs continuation, dropout, graduation, earnings
Education production function
Todd and Wolpin (2003)
Achievement of student \(i\) in family \(j\) at age \(a\)
\[ q_{ija} = q_a\left(\mathbf{F}_{ij}(a), \mathbf{S}_{ij}(a), \mu_{ij0}, \varepsilon_{ija}\right) \]
\(\mathbf{S}_{ij}(a)\) history of school inputs up to age \(a\)
\(\mu_{ij0}\) initial skill endowment
\(\varepsilon_{ija}\) measurement error in output
\(q_a(\cdot)\) age-dependent production function
Education production function
Todd and Wolpin (2003): Contemporaneous specification
\[ q_{ija} = q_a(F_{ija}, S_{ija}) + \varepsilon_{ija} \]
Strong assumptions:
- Only current inputs are relevant OR inputs are stable over time
- Inputs are uncorrelated with \(\mu_{ij0}\) or \(\varepsilon_{ija}\)
Necessary when there (were) severe data limitations
Inputs themselves, as well as their relevance for production function, vary with age of child.
Parental investments depend on (perceptions) of initial endowment.
Education production function
Todd and Wolpin (2003): Value-added specification
\[ q_{ija} = q_a\left(F_{ija}, S_{ija}, \color{#9a2515}{q_{a-1}\left[F_{ij}(a - 1), S_{ij}(a - 1), \mu_{ij0}, \varepsilon_{ij, a - 1}\right]}, \varepsilon_{ija}\right) \]
Typical empirical estimation assumes linear separability and \(q_a(\cdot) = q(\cdot)\):
\[ q_{ija} = F_{ija} \alpha_F + S_{ija} \alpha_S + \gamma q_{ij, a - 1} + \nu_{ija} \]
Additional assumptions implied:
- Past input effects decay at the same rate \(\gamma\)
- Shocks \(\varepsilon_{ija}\) are serially correlated with persistence \(\gamma\)
Assume a very simple linear production function with full histories
\[ q_{ija} = X_{ija}\alpha_1 + X_{ij, a - 1}\alpha_2 + \ldots + X_{ij1} \alpha_a + \beta_a \mu_{ij0} + \varepsilon_{ija} \]
Then, same equation at \(a - 1\) is
\[ \gamma q_{ij, a - 1} = \gamma X_{ij, a - 1}\alpha_1 + \ldots + \gamma X_{ij1} \alpha_{a - 1} + \gamma \beta_{a - 1} \mu_{ij0} + \gamma\varepsilon_{ij, a - 1} \]
The difference (or value added) is
\[ q_{ija} - \gamma q_{ij, a - 1} = X_{ija}\alpha_1 + X_{ij, a - 1} \left(\alpha_2 - \gamma \alpha_1\right) + \ldots + X_{ij1}\left(\alpha_a - \gamma \alpha_{a - 1}\right) + \left(\beta_a - \gamma\beta_{a - 1}\right)\mu_{ij0} + \varepsilon_{ija} - \gamma \varepsilon_{ij, a - 1} \]
Therefore, it is clear that for this expression to be equivalent to the above regression equation, the following should hold
\[ \begin{align} \alpha_v &= \gamma \alpha_{v - 1} \\ \beta_v &= \gamma \beta_{v - 1} \end{align}, \qquad \forall v \in 1, \ldots, A \]
In addition, it also highlights that the regression error term \(\nu_{ija} = \varepsilon_{ija} - \gamma\varepsilon_{ij, a - 1}\). So, consistent estimation requires that \(\varepsilon_{ija}\) is serially correlated with persistence exactly equal to \(\gamma\). In that case \(\nu_{ija}\) is white noise and uncorrelated with \(q_{ij, a - 1}\).
If any of these assumptions don’t hold, then estimates will be biased.
Education production function
Todd and Wolpin (2003): Cumulative specification
Still assume linear separability:
\[ q_{ija} = \sum_{t = 1}^a X_{ijt} \alpha_{a - t + 1}^a + \beta_a \mu_{ij0} + \varepsilon_{ij}(a) \]
Estimation strategies:
- Within-family: \(q_{ija} - q_{i^\prime ja}\) for siblings \(i\) and \(i^\prime\)
- Within-age: \(q_{ija} - q_{ija^\prime}\) for ages \(a\) and \(a^\prime\)
Each with their own caveats
Within-family
Siblings observed at different times and/or ages
Only gets rid of family-specific initial endowments, but not child-specific \(\mu_{ij0} - \mu_{i^\prime j0} \neq 0\)
So, consistent estimation only possible if input choices are independent of child-specific endowments!
Furthermore, assumes that there are no spillover effects between siblings. If this assumption is violated then \(\varepsilon_{ij}(a)\) may influence input choices for sibling \(i^\prime\)!
Within-child
Assumes that \(\beta_a = \beta, \forall a\). Otherwise, differencing across ages does not get rid of initial endowment \(\mu_{ij0}\).
Assumes that input choices do not depend on past outcomes.
All in all, estimating edu production functions is really really hard!
Education production function
(Quasi-)Experimental estimations
Nature vs nurture
Twin models (ACDE)
Genetic effects:
additive \(A\)
non-additive (dominant) \(D\)
Environment effects:
common \(C\): by definition correlation = 1
idiosyncratic \(E\): by definition uncorrelated between twins
Correlation in genetic effects:
Monozygotic twins
- these siblings have exactly equal genotypes, both in terms of additive effects and dominant effects (perfect copies)
Dizygotic twins (as well as normal siblings)
in an additive sense, we are interested what is the probability of receiving a given allele from a parent. Answer, 50% (meiosis). At the level of entire genotypes, this means that on average siblings share 50% of their genotypes.
For the dominant effect, we want to know what is the chance of receiving dominant allele from both parents. Answer, 50% * 50% = 25% (also meiosis).
Key equations:
\[ \begin{align} VAR &= A^2 + D^2 + C^2 + E^2 \\ COV_{MZ} &= A^2 + D^2 + C^2 \\ COV_{DZ} &= \frac{1}{2} A^2 + \frac{1}{4} D^2 + C^2 \\ h^2 &= \frac{A^2 + D^2}{VAR} \end{align} \]
The full ACDE model is underidentified: not enough covariances. Thus, have to choose between ACE or DCE models!
Nature vs nurture
Twin models: Polderman et al. (2015)
Meta-analysis of >17,000 twin-analyses (>1,500 cognitive traits)
- 47% of variation due to genetic factors
- 18% of variation due to shared environment
Adoption studies
Overall environment factors ~50%
Most readily amenable to policies \(\Rightarrow\) attractive
Large policy discussion about school resources
Productivity of school inputs
School spending: review by Handel and Hanushek (2023)
Exogenous variation due to court decisions or legislative action
Quasi-experimental variation in recent studies:
court-mandated
legislative action
Besides high variability in estimates, these are not super useful because not clear what exactly money is being spent on
Productivity of school inputs
School spending: review by Handel and Hanushek (2023)
Large variation of spending effects on test scores
Not clear how money was used
Role of differences in regulatory environments
Similar results for participation rates are all positive (mostly significant)
Bridge the participation results to class sizes on next slide.
Productivity of school inputs
Class size: Angrist and Lavy (1999)
Quasi-experimental variation in Israel: Maimonides rule
Rule from Babylonian Talmud, interpreted by Maimonides in XII century:
If there are more than forty [students], two teachers must be appointed
Sharp drops in class sizes with 41, 81, … cohort sizes in schools
Regression discontinuity design (RDD)
Classical paper!
Productivity of school inputs
Class size: Angrist and Lavy (1999)
Maimonides rule: \(f_{sc} = \frac{E_s}{\text{int}\left(\frac{E_s - 1}{40}\right) + 1}\)
“Fuzzy” RDD
First stage: \(n_{sc} = X_{sc} \pi_0 + f_{sc} \pi_1 + \xi_{sc}\)
Second stage: \(y_{sc} = X_{s}\beta + n_{sc}\alpha + \eta_s + \mu_c + \epsilon_{sc}\)
Productivity of school inputs
Class size: Angrist and Lavy (1999)
Productivity of school inputs
Class size: Angrist and Lavy (1999)
Grade 5 | Grade 4 | |||
---|---|---|---|---|
Reading | Math | Reading | Math | |
Class size | -0.410 | -0.185 | -0.098 | 0.095 |
(0.113) | (0.151) | (0.090) | (0.114) | |
Mean score | 74.5 | 67.0 | 72.5 | 68.7 |
SD score | 8.2 | 10.2 | 7.8 | 9.1 |
Obs | 471 | 471 | 415 | 415 |
Productivity of school inputs
Class size: Krueger (1999), Chetty et al. (2011)
Project STAR: 79 schools, 6323 children in 1985-86 cohort in Tennessee
Randomly assigned students into
small class (13-17 students)
large class (20-25 students)
\[ Y = \alpha + \beta SMALL + X\delta +\varepsilon \]
Randomization means students between classes are on average similar
\(\boldsymbol{\Rightarrow} \color{#9a2515}{\boldsymbol{\beta}}\) is causal
Krueger (1999) is the classical paper; however, Chetty et al. (2011) provide updated results accounting/fixing several issues with the empirical strategy
Attrition due to moving away/grade retention
Some students (not part of initial cohort) joined participating schools in grades 1-3
Randomised into small/large classes upon entry
Spent < 4 years in the respective classes
Random assignment into class type (level 1) and classroom (level 2; not documented)
Some students switched to a different class type
assigned to small class: 2.27 years in small class
assigned to large class: 0.13 years in small class
Productivity of school inputs
Class size and quality: Chetty et al. (2011)
Dependent variable | \(SMALL\) | Class quality1 |
---|---|---|
Test score percentile (at \(t = 0\)), % | 4.81 (1.05) |
0.662 (0.024) |
College by age 27, % | 1.91 (1.19) |
0.108 (0.053) |
College quality, $ | 119 (96.8) |
9.328 (4.573) |
Wage earnings, $ | 4.09 (327) |
53.44 (24.84) |
Mention fade-out and reemergence
Almost no effect on test scores beyond the first year in the project (fade-out)
Significant positive impact on adult earnings (re-emergence)
A potential mechanism of re-emergence: noncognitive skills (next slide)
Productivity of school inputs
Class size and quality: Chetty et al. (2011)
Productivity of school inputs
Teacher incentives: Fryer (2013)
2-year pilot program in 2007 among lowest-performing schools in NYC
- 438 eligible schools, 233 offered treatment, 198 accepted, 163 control
Relative rank of schools in each subscore
Bonus sizes:
- $3,000/teacher if 100% target
- $1,500/teacher if 75% target
- Existing studies mostly focus on effort margin, and virtually no paper studies selection margin
Productivity of school inputs
Teacher incentives: Fryer (2013)
Instrumental variable approach (LATE = ATT):
\[ \begin{align} Y &= \alpha_2 + \beta_2 X + \pi_2 ~ \text{incentive} + \epsilon \\ \text{incentive} &= \alpha_1 + \beta_1 X + \pi_1 ~ \text{treatment} + \xi \end{align} \]
Productivity of school inputs
Teacher incentives: Fryer (2013)
Elementary | Middle | High | |
---|---|---|---|
English | -0.010 (0.015) |
-0.026 (0.010) |
-0.003 (0.043) |
Math | -0.014 (0.018) |
-0.040 (0.016) |
-0.018 (0.029) |
Science | -0.018 (0.037) |
||
Graduation | -0.053 (0.026) |
Productivity of school inputs
Teacher incentives: Fryer (2013)
Incentive size was too small (\(\approx 4.1\)% of annual salary)
Incentive scheme too complex to nudge a certain behaviour
Bonuses were distributed \(\approx\) equally \(\Rightarrow\) free-riding problem
Incentivising output vs input
Effort of existing teachers vs selection into teaching
Productivity of school inputs
Teacher incentives: Biasi (2021)
Change in teacher pay scheme in Wisconsin in 2011:
- seniority pay (SP): collective scheme based on seniority and quals
- flexible pay (FP): bargaining with individual teachers
Main results:
FP \(\uparrow\) salary of high-quality teachers relative to low-quality
high-quality teachers moved to FP districts (low-quality to SP)
teacher effort \(\uparrow\) in FP districts relative to SP
student test scores \(\uparrow 0.06\sigma\) (1/3 of effect of \(\downarrow\) class size by 5)
- General equilibrium: what happens if all districts switch to FP?
Productivity of non-school inputs
Peer effects: Abdulkadiroğlu, Angrist, and Pathak (2014)
Prestigious exam schools in Boston and New York
Students from public schools can transfer at 7th or 9th grades
Admission based on test scores, GPA and school preference ranking
Selectivity affects peer composition at either side of the cutoff
Productivity of non-school inputs
Peer effects: Abdulkadiroğlu, Angrist, and Pathak (2014)
Source: Abdulkadiroğlu, Angrist, and Pathak (2014), Figure 2
Productivity of non-school inputs
Peer effects: Abdulkadiroğlu, Angrist, and Pathak (2014)
Productivity of non-school inputs
Peer effects: Abdulkadiroğlu, Angrist, and Pathak (2014)
No effect of peer composition on academic success variables!
Dale and Krueger (2002) study admission into selective colleges in the US
No effect on average earnings
Positive effect on earnings of students from low-income families
Kanninen, Kortelainen, and Tervonen (2023): selective schools in Finland
No effect on high school exit exam score
Positive effect on university enrollment and graduation rates
No impact on income
Abdulkadiroğlu, Angrist, and Pathak (2014)
No visible effect on academic outcomes. Similarly for test scores in later grades.
External validity: the applicant kids are very different from average kids.
Preparing for an admission may itself be a productive process/treatment.
Exposure to clubs and activities may change attitudes, opinions; but these things may not correlate well with outcomes considered in the study.
The study does not consider labour market outcomes.
- Maybe networks
Kanninen, Kortelainen, and Tervonen (2023)
Advocate that selective HS changes edu preferences, but not skills!
There are other studies that show positive effects of selective schools:
Pop-Eleches and Urquiola (2013) Romania \(\uparrow\) high-stake test scores
Jackson (2010) Trinidad and Tobago: large score gains
Overall, there is little consensus on peer effects, selectivity and tracking in education. Some find positive, some find zero effects. Hard to study. A lot of work continues.
Productivity of non-school inputs
Curriculum: Alan, Boneva, and Ertac (2019)
RCT among schools in remote areas of Istanbul
Carefully designed curriculum promoting grit (\(\geq 2\)h/week for 12 weeks)
Treated students are more likely to
- set challenging goals
- exert effort to improve their skills
- accumulate more skills
- have higher standardised test scores
These effects persist 2.5 years after the intervention
animated videos
mini case studies
classroom activities
highlight
plasticity of brain vs innate ability idea
role of effort in enhancing skills
constructive interpretation of setbacks
importance of goal setting
Productivity of non-school inputs
Curriculum: other evidence
Squicciarini (2020): adoption of technical education in France in 1870-1914
- higher resistance in religious areas, led to lower economic development
Machin and McNally (2008): ‘literacy hour’ introduced in UK in 1998/99
highly structured framework for teaching
\(\uparrow\) English and reading skills of primary schoolchildren
possibility that better curriculum at early stages “frees up” resources at later stages
not studied the longer-run effects
Summary
Academic achievement is complex function of student, parent, school and non-school inputs
Measuring achievement can also be difficult
Genetic and environmental factors from twin studies almost 50/50
Large variation in school resource effects (from \(\ll 0\) to \(\gg 0\))
- How resources are used?
- Which resources are most effective?
Studies of class size, teacher incentives, peer effects and curricula
Another (often overlooked) step is scaling up to the population
Next: Technological shift and labour markets
References
Footnotes
Besides size, experiment generated random variations in class quality (due to teachers, peers, …)↩︎