Abstract
The effect of a reduced pupil–teacher ratio has mainly been investigated as that of reduced class size. Hence we know little about alternative methods of reducing the pupil–teacher ratio. Deploying additional teachers in selected subjects may be a more flexible way, both pedagogically and financially, to exploit the opportunities for adapting instruction inherent in reducing the number of students under a teacher’s responsibility. In this paper, we discuss limitations to previous class-size research and suggest more flexible ways to implement a reduced pupil–teacher ratio. One alternative approach is illustrated with a change in national policy in Norway to increase teacher density as well as research following this initiative.
Full
Article
ERCT Criteria Breakdown
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Level 1 Criteria
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C
Class-level RCT
- The paper does not describe any randomization at the class level.
Relevant Quotes:
1) "To illustrate how an alternative approach to a reduced PTR
might be implemented, the last part of this paper will be devoted to
describing a change in Norwegian educational policy..."
Detailed Analysis:
The authors explicitly state that the paper’s final section is devoted to describing a policy change and a research initiative, rather than reporting an original class-level experimental study. There is no description of any random assignment of classes to different conditions in this paper.
Final sentence: The Class-level RCT criterion is not met because this paper does not report an actual class-level randomized trial.
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E
Exam-based Assessment
- No standardized exam-based assessment is implemented in the paper.
Relevant Quotes:
1) "Students’ skills in mathematics are measured through short tests
before and during the intervention (pre-test, intermediary tests),
and the Norwegian national test in numeracy for fifth-grade students
will serve as a post-test for all four cohorts of students."
Detailed Analysis:
Although the paper describes plans to use a standardized national exam in the 1+1 project, it does not itself administer or report any such exam-based outcomes. It remains a conceptual design.
Final sentence: The Exam-based Assessment criterion is not met because the paper does not implement any standardized exam-based outcome assessment.
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T
Term Duration
- No term-long outcome measurement is reported in the paper.
Relevant Quotes:
1) "The treatment classes received an additional teacher in Norwegian
lessons, 8 × 45 min a week, for 38 weeks, in grades 1 and 2."
2) "The treatment effects on the students’ motivation and literacy skills
will be evaluated immediately after the intervention and at a two-
year follow-up."
Detailed Analysis:
The paper outlines a multi-year intervention timeline but does not report measured outcomes at least one term after the start. It only describes when outcomes will be collected in theory.
Final sentence: The Term Duration criterion is not met because no term-long outcomes are actually reported.
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D
Documented Control Group
- Control group demographics and baseline data are not provided.
Relevant Quotes:
1) "At each school there was one treatment class and one control class.
... The control classes received no additional teaching resources."
Detailed Analysis:
While the design includes control classes with business-as-usual instruction, the paper provides no demographic or baseline data for those controls, preventing a proper comparison.
Final sentence: The Documented Control Group criterion is not met because the control group’s characteristics are not detailed.
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Level 2 Criteria
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S
School-level RCT
- No school-level random assignment is executed as part of this paper.
Relevant Quotes:
1) "An RCT is being carried out during four academic years (2016–2020).
The schools are divided into two groups of equal size – a treatment
group (80 schools) and a comparison group (82 schools)."
Detailed Analysis:
The paper describes a school-level randomization design but does not itself execute it within its own study—this discussion remains descriptive, not demonstrative.
Final sentence: The School-level RCT criterion is not met because no actual school-level randomization is reported here.
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I
Independent Conduct
- The study was conducted by the intervention's own authors.
Relevant Quotes:
1) "Both projects involve a frequent dialogue and regular feedback
meetings with the participating schools and municipalities..."
Detailed Analysis:
The authors describe close involvement in implementation and evaluation, implying that the same team designed and conducted the trials without third-party oversight.
Final sentence: The Independent Conduct criterion is not met because there is no indication of an external evaluation team.
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Y
Year Duration
- No outcomes tracked over a full academic year are provided.
Relevant Quotes:
1) "An RCT is being carried out during four academic years (2016–2020)."
2) "…the duration of intervention was reduced from 4 to 2 years;
interventions were terminated after the 2017/2018 academic year."
Detailed Analysis:
Both described projects span more than one academic year, but the paper itself does not report outcomes over a full year; it only outlines the planned duration.
Final sentence: The Year Duration criterion is not met because no year-long follow-up results are reported.
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B
Balanced Resources
- Treatment classes had extra teacher time; controls did not.
Relevant Quotes:
1) "The control classes received no additional teaching resources."
Detailed Analysis:
The intervention added teaching resources to treatment classes, while control classes did not receive equivalent resources. Because extra teacher time is the treatment variable, no balancing was needed for controls—but this leads to an imbalance per ERCT rules.
Final sentence: The Balanced Resources criterion is not met due to an inherent resource imbalance by design.
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Level 3 Criteria
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R
Reproduced Results
- No independent replication of the interventions is reported.
Relevant Quotes:
1) "Bonesrønning et al. (2022) investigate small-group instruction in
mathematics and find similar effects..."
Detailed Analysis:
Although an independent team studied small-group math instruction, there is no documented replication of the Two Teachers literacy intervention by another research group. No true independent reproduction of the paper’s specific trials is cited.
Final sentence: The Reproduced criterion is not met because no independent replication of these exact interventions is found.
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A
All Exams
- Outcomes measured only in targeted subjects, not across all.
Relevant Quotes:
1) "The treatment effects on the students’ motivation and literacy
skills will be evaluated immediately after the intervention and at a
two-year follow-up."
2) "the Norwegian national test in numeracy for fifth-grade students
will serve as a post-test for all four cohorts of students."
Detailed Analysis:
Each project is confined to one subject area (literacy or math). The paper does not assess impacts across all core subjects, so potential trade-offs are not examined.
Final sentence: The All-subject Exams criterion is not met because assessments are limited to the targeted subjects.
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G
Graduation Tracking
- No long-term tracking through graduation is provided.
Relevant Quotes:
1) "The treatment effects... will be evaluated immediately after the
intervention and at a two-year follow-up."
Detailed Analysis:
The paper describes follow-up to two years post-intervention, not through any graduation milestone. No tracking until graduation is reported here.
Final sentence: The Graduation Tracking criterion is not met because participants were not followed through to graduation.
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P
Pre-Registered Protocol
- The RCT was preregistered on OSF prior to data collection.
- OSF pre-registration. doi:10.17605/OSF.IO/YWQVC.
Relevant Quotes:
1) "...the design had to be changed compared with the original plan as
reported in the study protocol." (page 150)
2) "OSF pre-registration. doi:10.17605/OSF.IO/YWQVC."
Detailed Analysis:
The mention of modifying a predefined study protocol shows the existence of a prespecified plan. Furthermore, an external follow-up paper explicitly cites OSF preregistration before data collection, confirming a formal preregistration.
Final sentence: The Pre-registered Protocol criterion is met because the interventions were formally preregistered before data collection.
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