What selective schooling and test preparation demonstrably change, and what they don't. 12 verified findings — quoted verbatim, fully cited, independently checked (register v1.3.0, verified 2026-08-24).
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Start with the finding that's easiest to skip past: once you account for who gets in, attending a selective school adds little or nothing to a student's achievement. This isn't a fringe result. The strongest causal evidence internationally comes from regression-discontinuity studies of Boston and New York exam schools, which exploit the sharp admissions cutoff to compare students just above and just below the line — students who are, for all practical purposes, identical except for which school they attend. The result: "little effect of exam school offers on most students' achievement," and the authors conclude the intense competition for seats "does not appear to be justified by improved learning for a broad set of students" [TST-01]. Australia's own research points the same way. The first regression-discontinuity and matching study of an Australian selective system, using Victorian data, found only "small positive effects at best" on university entrance results once students' existing high achievement and aspiration were accounted for [TST-02]. The first such study for New South Wales — the country's oldest and largest selective system — found offers had "only scattered and mostly insignificant impacts on overall student achievement," though low-SES students who did get in seemed to benefit more, while remaining underrepresented in the intake to begin with [TST-03]. The common thread across Boston, New York, Victoria and NSW is that the huge gap in average achievement between selective and non-selective schools is mostly explained by who walks through the door, not by anything the school subsequently does. One UK study, using a historical grammar-school assignment formula, did find a genuine elite-school effect on years of completed education — but even there the downstream effects were uneven and not a straightforward achievement bump: gains in income for women, none for men, and a fertility cost for women, which is a different kind of finding altogether, not evidence that the school made students better at exams [TST-04]. In Victoria today, roughly 1,000 Year 9 places are contested across four selective schools each year [TST-05], and nationally, as of 2015, 25 selective high schools and a further 70 select-entry programs operated across four states [TST-09] — a lot of family effort and money chasing a prize that, on the best available evidence, is substantially an illusion of the sorting process itself.
If the school itself doesn't do much, does preparing for the entrance test do anything? Here the evidence is more encouraging, but modest, and it discriminates sharply between good and bad preparation. A 2025 meta-analysis of 28 experimental and quasi-experimental studies found that structured test preparation does significantly improve scores on large-scale educational tests, but the effect is small to moderate — an effect size of g=.26 — and, crucially, it is not driven by simply doing lots of practice items. The gains came from workbook use, training in socio-affective strategies (managing anxiety, pacing, confidence), and explicit instruction in test-taking skills; the study found "little evidence of practice effect" from sample items and practice tests alone [TST-06]. A separate, older but well-established meta-analysis in the personnel-selection literature — 50 studies, over 134,000 participants, on retesting with cognitive-ability-style tests, the kind of reasoning test that selective-entry and scholarship exams most resemble — found essentially the same quarter-standard-deviation gain (g=.26) from taking a similar test twice, with larger gains when practice was combined with actual coaching or when identical test forms were reused [TST-07]. US research on SAT coaching, using propensity-score matching to correct for the fact that families who seek coaching differ systematically from those who don't, found real but modest gains — roughly 11 to 15 points on maths, 6 to 9 on verbal — and, tellingly, those gains were substantially larger for higher-SES students than for lower-SES students using the same kind of preparation (15 vs 5 points on maths; 9 vs 2 on verbal) [TST-08]. Put together: coaching works, a bit, mostly through quality of preparation rather than sheer volume of drilling, and the families with more resources tend to extract more benefit from it than families with less — which is worth sitting with rather than glossing over.
The third thread is what high-stakes testing does to teaching itself, and here the Australian evidence is direct and uncomfortable. A foundational qualitative synthesis of 49 studies found the dominant, most common effect of high-stakes testing on classrooms is that curriculum narrows to what's tested, knowledge gets fragmented into test-sized pieces, and pedagogy shifts toward teacher-centred instruction — though a significant minority of tests, depending on how they're structured, produced the opposite: curriculum expansion and more student-centred teaching [TST-10]. Australia's own 2020 independent NAPLAN Review reached a strikingly similar and specific conclusion about writing: restricting the writing test to narrative and persuasive genres, with the genre often announced in advance, "led to very formulaic writing in students' responses to the prompt and, as a further unintended consequence, to very formulaic teaching of writing in some schools as they seek to prepare students for the NAPLAN writing test" — a finding serious enough that the review recommended withdrawing the writing test from census testing altogether [TST-11]. The review's stakeholder testimony makes the mechanism concrete: teachers described being coached into "gaming" the marking criteria, producing what one respondent called "cookie cutter" writing, and the panel's own analysis linked this directly to test preparation displacing the planned curriculum in the lead-up to testing — NAPLAN prep becoming, in the report's words, "the proxy curriculum" [TST-12]. This is the washback effect in its plainest form: when a test rewards a formula, schools teach the formula, and something real is lost in the process.
Put the three threads together and the honest picture for a family weighing selective-entry or scholarship testing is this. The school itself is very unlikely to be the transformative factor everyone assumes it is — the achievement gap between selective and comprehensive schools is mostly the students who were already there, not something the building or the label adds. Coaching for the entrance exam can move the needle, but only modestly, and only when it's built around real skill development — strategy, structure, confidence, exam craft — rather than repetition for its own sake; volume of practice items is close to worthless on its own. And the surrounding culture of high-stakes testing has a well-documented tendency to narrow teaching toward formula, which is precisely the trap a family should want their child to avoid, not walk into. None of this is an argument against preparing. Confidence going into an exam matters, access to selective pathways matters for families who want them, and a quarter-standard-deviation gain is real value when a single test is the gate. But it is an argument for being honest about what preparation actually buys: not a guaranteed changed trajectory, and not best pursued through drilling more of the same formulaic material a high-stakes test tends to reward. The durable asset a student carries out of a genuine test-preparation period is the literacy and reasoning skill built along the way — the actual capacity to read closely, argue clearly, and write well under pressure — which persists long after the specific exam is behind them, whether or not they get the placement. That is the case for teaching craft rather than test tricks: not because test tricks don't work at all, but because the evidence says they barely do, while the underlying skill is what was worth building regardless of the outcome on the day.
US regression-discontinuity research on elite exam-school admissions (Boston and New York) finds little to no achievement gain from attending, despite the schools' large peer-achievement gap — the perceived superiority is largely explained by intake selection, not school effects.
Our estimates show little effect of exam school offers on most students' achievement. ... the intense competition for exam school seats does not appear to be justified by improved learning for a broad set of students.
The first regression-discontinuity and matching-based estimates of the causal effect of attending an academically selective high school in an Australian state (using Victorian and other state data) find only small positive effects at best on university entrance results, once students' pre-existing high achievement and aspiration are accounted for.
The estimates point to small positive effects at best on university entrance results from attending the selective schools. Overall, the small selective school effect appears to reflect the high levels of educational aspiration of both selective students as well as applicants who attended other schools.
UK evidence using an instrumental-variables design around a historical elite/non-elite secondary school assignment formula finds attending an elite school produced large gains in completed education, but the pattern of effects on later-life labour market outcomes was uneven by sex (positive income effects for women, none for men) and came with a significant fertility cost for women — i.e. the causal gains were not simply general achievement gains.
Using instrumental variables methods that exploit the school assignment formula, we find that elite school attendance had large impacts on completed education. For women, we find that elite school attendance generated positive effects on labor market outcomes and significant decreases in fertility; for men, we find no elite school impacts on any of these later-life outcomes.
Victoria has four academically selective-entry government high schools (Melbourne High School, The Mac.Robertson Girls' High School, Nossal High School, Suzanne Cory High School), with approximately 1,000 Year 9 places offered across the four schools each year.
Victoria has four selective entry high schools that provide a specialist environment for academically high-achieving students in Years 9 to 12. ... Each year approximately 1,000 places are available for Year 9 entry across the four selective entry high schools (SEHS).
A 2025 meta-analysis of 28 experimental/quasi-experimental studies finds that structured test-preparation interventions produce a small-to-moderate, statistically significant improvement in students' scores on large-scale educational tests, with the effect driven mainly by workbook use, socio-affective strategy training, and explicit test-taking-skills instruction — not by mere repeated exposure to practice items.
Results from 28 included studies suggested that students' test performance can be significantly improved by test preparation (g = .26, 95% CI = .10-.42). Using workbooks, developing students' socio-affective strategies, and teaching test-taking skills were found to be significant moderators of the test preparation effect. Little evidence of practice effect (i.e., using sample items and practice tests) on test preparation was found in the current study.
A meta-analysis of 50 studies (107 samples, ~134,000 participants) on retesting with cognitive-ability-style tests finds an average score gain of about a quarter of a standard deviation (g=.26) simply from taking the same style of test twice, and that this gain is larger when retesting is combined with explicit coaching or when identical test forms are reused — evidence directly relevant to ability-style selective-entry and scholarship exams, which resemble cognitive ability tests more than curriculum-based achievement tests.
This study uses meta-analysis to summarize the results of 50 studies of practice effects for tests of cognitive ability. Results from 107 samples and 134,436 participants revealed an adjusted overall effect size of .26. Moderator analyses indicated that effects were larger when practice was accompanied by test coaching, and when identical forms were used.
As of 2015 there were 25 academically selective high schools across four Australian states (New South Wales, Queensland, Victoria and Western Australia), plus a further 70 schools offering select-entry programs for a subset of classes rather than the whole school.
In 2015, there were 25 selective high schools across the states of New South Wales (NSW), Queensland, Victoria and Western Australia. Most of these schools admit students based on entrance exams or tests... There were also 70 other high schools in these same states offering select-entry programs, where one or more classes of students (as compared with all students) are admitted in a similar process involving tests and interviews.
Wayne Au's qualitative meta-synthesis of 49 studies on high-stakes testing finds the dominant effect is that curriculum content narrows to tested subjects, knowledge gets fragmented into test-related pieces, and pedagogy shifts toward teacher-centred instruction — though a significant minority of cases showed the opposite (curriculum expansion, knowledge integration, more student-centred pedagogy), with the direction of the effect depending on how the test itself is structured.
the primary effect of high-stakes testing is that curricular content is narrowed to tested subjects, subject area knowledge is fragmented into test-related pieces, and teachers increase the use of teacher-centered pedagogies. However, in a significant minority of cases, certain types of high-stakes tests have led to curricular content expansion, the integration of knowledge, and more student-centered, cooperative pedagogies.
Australia's 2020 independent NAPLAN Review found that the restriction of the NAPLAN writing test to narrative and persuasive genres (with the genre often announced in advance) led to very formulaic student writing and, as an unintended consequence, formulaic teaching of writing in some schools as they prepared students for the test — one of the review's central criticisms, leading to a recommendation that the writing test be withdrawn from census testing and redeveloped.
The restriction of the writing genres to narrative and persuasive, with the specific genre being announced in advance in the early years of NAPLAN, has led to very formulaic writing in students' responses to the prompt and, as a further unintended consequence, to very formulaic teaching of writing in some schools as they seek to prepare students for the NAPLAN writing test.
The 2020 NAPLAN Review documented direct classroom testimony that teachers were coached into 'gaming' the writing marking criteria to maximise scores, describing the practice as reducing writing pedagogy to a formula ('cookie-cutter' writing) rather than genuine composition, and linked this to a broader shift where NAPLAN test preparation itself displaced planned curriculum in the weeks before testing.
Where this displacement of curriculum occurred, NAPLAN test preparation became the proxy curriculum and teaching writing was reduced to a dominant focus on the structure of the writing, the formula for producing the narrative or the persuasive form, with some commentary about maximising the score on writing through 'gaming' the criteria. In commenting on classroom preparation of students for NAPLAN writing, one respondent said "You're forensically taking out different things, and you can formulaically produce a response that maximises the result" (Member of the NAPLAN Review Practitioners' Reference Group)... "The richness of writing has been lost. 'Cookie cutter' writing is being produced" (Subject association).
The first regression-discontinuity study of NSW selective high schools (the oldest and largest selective system in Australia) finds that receiving an offer to attend a selective school has only scattered, mostly statistically insignificant effects on overall student achievement and participation in advanced coursework — while low-SES students who do get in appear to benefit more, yet remain underrepresented in the selective intake.
I find that receiving an offer to attend a selective school has only scattered and mostly insignificant impacts on overall student achievement and participation in advanced coursework. I do find suggestive evidence that selective schools benefit low socioeconomic status students, but that such students are typically underrepresented in selective schools, which has implications for Gifted and Talented education policy.
US SAT test-preparation research using propensity-score matching to correct for self-selection bias finds coaching produces modest score gains (roughly 11-15 points on math and 6-9 points on verbal), and that gains are larger for higher-SES students who use private tutoring or commercial coaching than for lower-SES students using the same preparation types — evidence that coaching effects on ability-style admissions tests are real but modest, and unevenly distributed by family resources.
For those students that have taken both the PSAT and SAT, effect estimates of roughly 11 to 15 points on the math section and 6 to 9 points on the verbal are found. Only the math effects are statistically significant. ... When coached students in the top SES quartile are compared to uncoached students in the top SES quartile, we find a mean difference of 15 points on SAT math scores. In contrast, amongst students in lower SES quartiles, coaching has only a 5 point effect. ... On the verbal section... the effect is 9 points for high SES students but just 2 points for lower SES students.
Cite any finding by its anchor — for example #TST-01 — and the link resolves to the claim, quote and source above. The verification protocol lives on the register’s main page.