Why English? | Reporting TIDieR-PHP Population Health and Policy Interventions Through Authority, Context, Variation and Fidelity

WHY ENGLISH?

Describe a population policy as the system of authority, organisations and variation that delivered it

Population health and policy interventions can be laws, taxes, organisational changes, environmental redesigns or public programmes. They are often delivered to whole communities through institutions rather than handed to one participant. A short policy name therefore tells readers very little about what was authorised, implemented or enforced.

TIDieR-PHP was published in The BMJ on 16 May 2018 as an adaptation of the Template for Intervention Description and Replication. Its nine items include sub-items for planned and unplanned variation and for strategies to maintain fidelity versus the delivery actually achieved.

English matters because words such as national, implemented and comprehensive can conceal different powers, organisations, dates, exceptions and local versions. A clear report helps students and decision-makers understand the intervention without assuming that detailed description proves effectiveness or makes one policy transferable everywhere.

READING ROUTE
Name and rationale

Identify the policy and its intended pathway.

READING ROUTE
Authority and delivery

Show materials, powers and organisations.

READING ROUTE
Place and time

Preserve geography, context and duration.

READING ROUTE
Variation and fidelity

Report local versions and actual delivery.

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Article contents

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1. Give the Intervention a Brief, Searchable Name
2. Explain Why the Intervention Should Work
3. Describe Physical and Informational Materials
4. Explain the Procedures, Processes and Enforcement
5. Identify Providers, Powers and Responsibilities
6. Describe Location, Geographical Scope and Context
7. State When the Intervention Began and How Long It Operated
8. Report Planned Variation Across Places and Groups
9. Report Unplanned Modification After Commencement
10. Describe Strategies Intended to Maintain Fidelity
11. Report the Delivery Actually Achieved
12. Connect Variation to Outcome Interpretation
13. Write a Bounded Transfer Statement

ORIENTATION

What this guide owns

Current fact check

TIDieR-PHP is a 2018 reporting guideline for public health, health systems, and social and environmental policy interventions. Its checklist has nine numbered items, with separate sub-items 8.1 and 8.2 for planned and unplanned variation and 9.1 and 9.2 for fidelity strategies and actual delivery.

Canonical boundary

This article owns reporting of population health and policy interventions with TIDieR-PHP. It does not own general TIDieR reporting, policy evaluation design, legal interpretation, implementation outcomes or claims that a policy will reproduce the same effects elsewhere.

Worked example

Every chapter returns to a fictional city-wide programme that changes school-zone street design and travel routines to support safer active journeys. It is fictional, low-stakes and educational; it does not report a real school, clinical decision or guaranteed outcome.

Did You Know? For tidier_php, complete reporting makes appraisal possible but does not perform the appraisal, remove bias or guarantee transfer.

Warm up with eduKate’s guides to explaining scientific evidence and asking better questions in class.

CHAPTER 1 OF 13

1. Give the Intervention a Brief, Searchable Name

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Why this move matters

Use an official or descriptive name and expand abbreviations so readers can identify the intervention across reports and jurisdictions.

Did You Know? TIDieR-PHP item 1 preserves an identifiable intervention label.

Treat the intervention as a public system

Use an official or descriptive name and expand abbreviations so readers can identify the intervention across reports and jurisdictions. Follow legislation, organisations, resources, enforcement and population reach rather than searching for one therapist-like delivery moment.

Map one implementation pathway

Apply the item to The programme is named School-Zone Active Journey Redesign rather than simply safety policy. Identify the authority, operational organisations, frontline actors, locations, dates and intended population effects, then show where variation entered.

Preserve place and history

Explain the political, cultural, socioeconomic and institutional conditions that make the intervention possible. These conditions help readers interpret transfer without implying that one setting is a universal template.

Separate description from evaluation

The same name may cover different legal or operational versions. Complete intervention reporting reveals what happened; it does not prove effectiveness, equity, legality or suitability for another jurisdiction.

Practical reader check

Point to the exact source or method sentence supporting the claim.
Name the person, setting, date, input and decision rule that could change its meaning.
Label the remaining uncertainty reported, inferred, contested or unknown.

Student, parent and career transfer

Make one evidence card for “Give the Intervention a Brief, Searchable Name”: source location, plain-language meaning, limit and next question. A parent or teacher can ask for one everyday explanation and one specialist explanation; both must preserve the same conditions. This habit supports public policy, population health, education administration, urban planning, programme evaluation and public communication without promising a grade, admission, funding decision or job.

CHAPTER 2 OF 13

2. Explain Why the Intervention Should Work

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Why this move matters

Describe the goals, policy theory, social or environmental mechanisms and assumptions connecting action to population outcomes.

Did You Know? The Why item makes the intervention theory visible without turning it into proof.

Treat the intervention as a public system

Describe the goals, policy theory, social or environmental mechanisms and assumptions connecting action to population outcomes. Follow legislation, organisations, resources, enforcement and population reach rather than searching for one therapist-like delivery moment.

Map one implementation pathway

Apply the item to Street changes and coordinated school routines are expected to alter perceived safety and travel choices. Identify the authority, operational organisations, frontline actors, locations, dates and intended population effects, then show where variation entered.

Preserve place and history

Separate description from evaluation

A plausible pathway is not evidence that every link occurred. Complete intervention reporting reveals what happened; it does not prove effectiveness, equity, legality or suitability for another jurisdiction.

Practical reader check

Point to the exact source or method sentence supporting the claim.
Name the person, setting, date, input and decision rule that could change its meaning.
Label the remaining uncertainty reported, inferred, contested or unknown.

Student, parent and career transfer

Make one evidence card for “Explain Why the Intervention Should Work”: source location, plain-language meaning, limit and next question. A parent or teacher can ask for one everyday explanation and one specialist explanation; both must preserve the same conditions. This habit supports public policy, population health, education administration, urban planning, programme evaluation and public communication without promising a grade, admission, funding decision or job.

CHAPTER 3 OF 13

3. Describe Physical and Informational Materials

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Why this move matters

List legislation, regulations, design standards, guidance, signs, training, communications and tools, with stable access details where possible.

Did You Know? Materials for policy staff and implementers are part of the intervention.

Treat the intervention as a public system

List legislation, regulations, design standards, guidance, signs, training, communications and tools, with stable access details where possible. Follow legislation, organisations, resources, enforcement and population reach rather than searching for one therapist-like delivery moment.

Map one implementation pathway

Apply the item to The report links the design manual, public notice, school briefing and implementation map. Identify the authority, operational organisations, frontline actors, locations, dates and intended population effects, then show where variation entered.

Preserve place and history

Separate description from evaluation

Documents may be revised or withdrawn, so version and date matter. Complete intervention reporting reveals what happened; it does not prove effectiveness, equity, legality or suitability for another jurisdiction.

Practical reader check

Point to the exact source or method sentence supporting the claim.
Name the person, setting, date, input and decision rule that could change its meaning.
Label the remaining uncertainty reported, inferred, contested or unknown.

Student, parent and career transfer

Make one evidence card for “Describe Physical and Informational Materials”: source location, plain-language meaning, limit and next question. A parent or teacher can ask for one everyday explanation and one specialist explanation; both must preserve the same conditions. This habit supports public policy, population health, education administration, urban planning, programme evaluation and public communication without promising a grade, admission, funding decision or job.

CHAPTER 4 OF 13

4. Explain the Procedures, Processes and Enforcement

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Why this move matters

Describe authorisation, planning, consultation, procurement, delivery, monitoring, enforcement and supporting activities.

Did You Know? TIDieR-PHP item 4 asks what was done and how at population scale.

Treat the intervention as a public system

Describe authorisation, planning, consultation, procurement, delivery, monitoring, enforcement and supporting activities. Follow legislation, organisations, resources, enforcement and population reach rather than searching for one therapist-like delivery moment.

Map one implementation pathway

Apply the item to The city approves designs, contractors alter crossings, schools change arrival routines and officers monitor compliance. Identify the authority, operational organisations, frontline actors, locations, dates and intended population effects, then show where variation entered.

Preserve place and history

Separate description from evaluation

A published rule does not establish operational implementation. Complete intervention reporting reveals what happened; it does not prove effectiveness, equity, legality or suitability for another jurisdiction.

Practical reader check

Point to the exact source or method sentence supporting the claim.
Name the person, setting, date, input and decision rule that could change its meaning.
Label the remaining uncertainty reported, inferred, contested or unknown.

Student, parent and career transfer

Make one evidence card for “Explain the Procedures, Processes and Enforcement”: source location, plain-language meaning, limit and next question. A parent or teacher can ask for one everyday explanation and one specialist explanation; both must preserve the same conditions. This habit supports public policy, population health, education administration, urban planning, programme evaluation and public communication without promising a grade, admission, funding decision or job.

CHAPTER 5 OF 13

5. Identify Providers, Powers and Responsibilities

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Why this move matters

Name legal status and powers, lead and field organisations, responsible staff, expertise, training and relationships among actors.

Did You Know? Item 5 extends provider reporting beyond individual practitioners.

Treat the intervention as a public system

Name legal status and powers, lead and field organisations, responsible staff, expertise, training and relationships among actors. Follow legislation, organisations, resources, enforcement and population reach rather than searching for one therapist-like delivery moment.

Map one implementation pathway

Apply the item to The transport authority has statutory powers while schools and contractors perform defined operational roles. Identify the authority, operational organisations, frontline actors, locations, dates and intended population effects, then show where variation entered.

Preserve place and history

Separate description from evaluation

A partnership list can obscure which body had authority to decide or enforce. Complete intervention reporting reveals what happened; it does not prove effectiveness, equity, legality or suitability for another jurisdiction.

Practical reader check

Point to the exact source or method sentence supporting the claim.
Name the person, setting, date, input and decision rule that could change its meaning.
Label the remaining uncertainty reported, inferred, contested or unknown.

Student, parent and career transfer

Make one evidence card for “Identify Providers, Powers and Responsibilities”: source location, plain-language meaning, limit and next question. A parent or teacher can ask for one everyday explanation and one specialist explanation; both must preserve the same conditions. This habit supports public policy, population health, education administration, urban planning, programme evaluation and public communication without promising a grade, admission, funding decision or job.

CHAPTER 6 OF 13

6. Describe Location, Geographical Scope and Context

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Why this move matters

State sites and boundaries plus relevant historical, cultural, socioeconomic or political conditions.

Did You Know? TIDieR-PHP item 6 explicitly includes geographical and contextual background.

Treat the intervention as a public system

State sites and boundaries plus relevant historical, cultural, socioeconomic or political conditions. Follow legislation, organisations, resources, enforcement and population reach rather than searching for one therapist-like delivery moment.

Map one implementation pathway

Apply the item to The programme covers selected school zones in one city, with neighbourhood characteristics described. Identify the authority, operational organisations, frontline actors, locations, dates and intended population effects, then show where variation entered.

Preserve place and history

Separate description from evaluation

A city-wide label may still exclude private roads or particular districts. Complete intervention reporting reveals what happened; it does not prove effectiveness, equity, legality or suitability for another jurisdiction.

Practical reader check

Point to the exact source or method sentence supporting the claim.
Name the person, setting, date, input and decision rule that could change its meaning.
Label the remaining uncertainty reported, inferred, contested or unknown.

Student, parent and career transfer

Make one evidence card for “Describe Location, Geographical Scope and Context”: source location, plain-language meaning, limit and next question. A parent or teacher can ask for one everyday explanation and one specialist explanation; both must preserve the same conditions. This habit supports public policy, population health, education administration, urban planning, programme evaluation and public communication without promising a grade, admission, funding decision or job.

CHAPTER 7 OF 13

7. State When the Intervention Began and How Long It Operated

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Why this move matters

Give authorisation, rollout, implementation and evaluation dates, duration and any repeated occasions or phases.

Did You Know? Item 7 separates implementation timing from a timeless policy label.

Treat the intervention as a public system

Give authorisation, rollout, implementation and evaluation dates, duration and any repeated occasions or phases. Follow legislation, organisations, resources, enforcement and population reach rather than searching for one therapist-like delivery moment.

Map one implementation pathway

Apply the item to Pilot construction begins in January, full operation in April and evaluation follows through December. Identify the authority, operational organisations, frontline actors, locations, dates and intended population effects, then show where variation entered.

Preserve place and history

Separate description from evaluation

A policy announcement date is not necessarily the exposure start date. Complete intervention reporting reveals what happened; it does not prove effectiveness, equity, legality or suitability for another jurisdiction.

Practical reader check

Point to the exact source or method sentence supporting the claim.
Name the person, setting, date, input and decision rule that could change its meaning.
Label the remaining uncertainty reported, inferred, contested or unknown.

Student, parent and career transfer

Make one evidence card for “State When the Intervention Began and How Long It Operated”: source location, plain-language meaning, limit and next question. A parent or teacher can ask for one everyday explanation and one specialist explanation; both must preserve the same conditions. This habit supports public policy, population health, education administration, urban planning, programme evaluation and public communication without promising a grade, admission, funding decision or job.

CHAPTER 8 OF 13

8. Report Planned Variation Across Places and Groups

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Why this move matters

Describe allowed local tailoring, eligibility, thresholds, options and reasons for different versions over place, subgroup or time.

Did You Know? Item 8.1 is dedicated to planned variation.

Treat the intervention as a public system

Describe allowed local tailoring, eligibility, thresholds, options and reasons for different versions over place, subgroup or time. Follow legislation, organisations, resources, enforcement and population reach rather than searching for one therapist-like delivery moment.

Map one implementation pathway

Apply the item to Schools choose among three approved arrival layouts according to street geometry. Identify the authority, operational organisations, frontline actors, locations, dates and intended population effects, then show where variation entered.

Preserve place and history

Separate description from evaluation

Planned flexibility may change dose or mechanism and should not be averaged away. Complete intervention reporting reveals what happened; it does not prove effectiveness, equity, legality or suitability for another jurisdiction.

Practical reader check

Point to the exact source or method sentence supporting the claim.
Name the person, setting, date, input and decision rule that could change its meaning.
Label the remaining uncertainty reported, inferred, contested or unknown.

Student, parent and career transfer

Make one evidence card for “Report Planned Variation Across Places and Groups”: source location, plain-language meaning, limit and next question. A parent or teacher can ask for one everyday explanation and one specialist explanation; both must preserve the same conditions. This habit supports public policy, population health, education administration, urban planning, programme evaluation and public communication without promising a grade, admission, funding decision or job.

CHAPTER 9 OF 13

9. Report Unplanned Modification After Commencement

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Why this move matters

State what changed unexpectedly, why, when, where and for whom, including operational disruption or political revision.

Did You Know? Item 8.2 makes post-start modification visible.

Treat the intervention as a public system

State what changed unexpectedly, why, when, where and for whom, including operational disruption or political revision. Follow legislation, organisations, resources, enforcement and population reach rather than searching for one therapist-like delivery moment.

Map one implementation pathway

Apply the item to Two locations delay barriers after emergency-access concerns and use temporary markings. Identify the authority, operational organisations, frontline actors, locations, dates and intended population effects, then show where variation entered.

Preserve place and history

Separate description from evaluation

Necessary adaptation can alter exposure and comparability. Complete intervention reporting reveals what happened; it does not prove effectiveness, equity, legality or suitability for another jurisdiction.

Practical reader check

Point to the exact source or method sentence supporting the claim.
Name the person, setting, date, input and decision rule that could change its meaning.
Label the remaining uncertainty reported, inferred, contested or unknown.

Student, parent and career transfer

Make one evidence card for “Report Unplanned Modification After Commencement”: source location, plain-language meaning, limit and next question. A parent or teacher can ask for one everyday explanation and one specialist explanation; both must preserve the same conditions. This habit supports public policy, population health, education administration, urban planning, programme evaluation and public communication without promising a grade, admission, funding decision or job.

CHAPTER 10 OF 13

10. Describe Strategies Intended to Maintain Fidelity

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Why this move matters

Report monitoring, contracts, inspections, training, feedback, escalation and resources used to keep delivery aligned with intent.

Did You Know? Item 9.1 covers actions taken to maintain fidelity.

Treat the intervention as a public system

Report monitoring, contracts, inspections, training, feedback, escalation and resources used to keep delivery aligned with intent. Follow legislation, organisations, resources, enforcement and population reach rather than searching for one therapist-like delivery moment.

Map one implementation pathway

Apply the item to A shared audit form and monthly cross-agency review track design and school-routine requirements. Identify the authority, operational organisations, frontline actors, locations, dates and intended population effects, then show where variation entered.

Preserve place and history

Separate description from evaluation

A strong assurance system does not prove that every site complied. Complete intervention reporting reveals what happened; it does not prove effectiveness, equity, legality or suitability for another jurisdiction.

Practical reader check

Point to the exact source or method sentence supporting the claim.
Name the person, setting, date, input and decision rule that could change its meaning.
Label the remaining uncertainty reported, inferred, contested or unknown.

Student, parent and career transfer

Make one evidence card for “Describe Strategies Intended to Maintain Fidelity”: source location, plain-language meaning, limit and next question. A parent or teacher can ask for one everyday explanation and one specialist explanation; both must preserve the same conditions. This habit supports public policy, population health, education administration, urban planning, programme evaluation and public communication without promising a grade, admission, funding decision or job.

CHAPTER 11 OF 13

11. Report the Delivery Actually Achieved

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Why this move matters

Provide reach, completed components, timing, compliance, enforcement and departures from the planned intervention.

Did You Know? Item 9.2 moves from fidelity strategy to observed delivery.

Treat the intervention as a public system

Provide reach, completed components, timing, compliance, enforcement and departures from the planned intervention. Follow legislation, organisations, resources, enforcement and population reach rather than searching for one therapist-like delivery moment.

Map one implementation pathway

Apply the item to The report shows which crossings, signs, staff routines and monitoring visits were completed at each site. Identify the authority, operational organisations, frontline actors, locations, dates and intended population effects, then show where variation entered.

Preserve place and history

Separate description from evaluation

An implementation percentage can hide which essential component was missing. Complete intervention reporting reveals what happened; it does not prove effectiveness, equity, legality or suitability for another jurisdiction.

Practical reader check

Point to the exact source or method sentence supporting the claim.
Name the person, setting, date, input and decision rule that could change its meaning.
Label the remaining uncertainty reported, inferred, contested or unknown.

Student, parent and career transfer

Make one evidence card for “Report the Delivery Actually Achieved”: source location, plain-language meaning, limit and next question. A parent or teacher can ask for one everyday explanation and one specialist explanation; both must preserve the same conditions. This habit supports public policy, population health, education administration, urban planning, programme evaluation and public communication without promising a grade, admission, funding decision or job.

CHAPTER 12 OF 13

12. Connect Variation to Outcome Interpretation

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Why this move matters

Explain how local versions, timing, enforcement and context are considered in analysis and conclusions.

Did You Know? Detailed description supports but does not replace a valid evaluation design.

Treat the intervention as a public system

Explain how local versions, timing, enforcement and context are considered in analysis and conclusions. Follow legislation, organisations, resources, enforcement and population reach rather than searching for one therapist-like delivery moment.

Map one implementation pathway

Apply the item to Outcome patterns are interpreted alongside the implemented version at each school zone. Identify the authority, operational organisations, frontline actors, locations, dates and intended population effects, then show where variation entered.

Preserve place and history

Separate description from evaluation

Post-hoc subgroup stories can overfit sparse local data. Complete intervention reporting reveals what happened; it does not prove effectiveness, equity, legality or suitability for another jurisdiction.

Practical reader check

Point to the exact source or method sentence supporting the claim.
Name the person, setting, date, input and decision rule that could change its meaning.
Label the remaining uncertainty reported, inferred, contested or unknown.

Student, parent and career transfer

Make one evidence card for “Connect Variation to Outcome Interpretation”: source location, plain-language meaning, limit and next question. A parent or teacher can ask for one everyday explanation and one specialist explanation; both must preserve the same conditions. This habit supports public policy, population health, education administration, urban planning, programme evaluation and public communication without promising a grade, admission, funding decision or job.

CHAPTER 13 OF 13

13. Write a Bounded Transfer Statement

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Why this move matters

State which functions may transfer, which forms depend on local authority and what new appraisal another setting would need.

Did You Know? TIDieR-PHP supports thoughtful adaptation rather than mechanical copying.

Treat the intervention as a public system

State which functions may transfer, which forms depend on local authority and what new appraisal another setting would need. Follow legislation, organisations, resources, enforcement and population reach rather than searching for one therapist-like delivery moment.

Map one implementation pathway

Apply the item to Another city could adapt the mechanism but must review its own legal powers, streets and school routines. Identify the authority, operational organisations, frontline actors, locations, dates and intended population effects, then show where variation entered.

Preserve place and history

Separate description from evaluation

Replication of form may fail when the implementation system differs. Complete intervention reporting reveals what happened; it does not prove effectiveness, equity, legality or suitability for another jurisdiction.

Practical reader check

Point to the exact source or method sentence supporting the claim.
Name the person, setting, date, input and decision rule that could change its meaning.
Label the remaining uncertainty reported, inferred, contested or unknown.

Student, parent and career transfer

Make one evidence card for “Write a Bounded Transfer Statement”: source location, plain-language meaning, limit and next question. A parent or teacher can ask for one everyday explanation and one specialist explanation; both must preserve the same conditions. This habit supports public policy, population health, education administration, urban planning, programme evaluation and public communication without promising a grade, admission, funding decision or job.

PRACTICE LAB

Build a policy decision trail

Student route

Choose one original report inside this guide’s scope.
Copy its objective and underline actor, action, context, evidence and intended decision.
Draw the specific reasoning chain used in this article.
Mark each step reported, inferred, contested or unknown.
Rewrite the conclusion so it preserves the narrowest important limitation.

Parent or teacher route

Ask the learner to explain describe a population policy as the system of authority, organisations and variation that delivered it twice: once to a classmate and once to a method specialist. Praise a precise correction and a well-stated unknown; both show disciplined attention to evidence.

Early-career route

Create a one-page tidier_php audit with source link, date checked, scope, method logic, decisive wording, contrary evidence, limit and next action. A colleague should be able to continue without guessing.

Decision rule

If a shorter explanation removes the condition that made the original claim true, it is not clearer yet. Restore the condition.

Continue with eduKate’s guides to reading course and career information and giving useful feedback in group projects.

USEFUL NEXT READING

Connect this narrow owner to its neighbour

Read the RAMESES II realist-evaluation guide for a related but different reader job. Return here when the question is specifically how to describe a population policy as the system of authority, organisations and variation that delivered it. This boundary keeps one canonical owner per intent.

For English practice across research, school and career communication, visit the Singapore English Tuition Centre learning site.

FREQUENTLY ASKED QUESTIONS

Questions students and parents often ask

What does TIDieR-PHP cover?

Public health, health systems, and social and environmental policy interventions.

How many numbered items are there?

Nine, with separate sub-items for variation and fidelity.

Is it only for randomised trials?

No. It complements the reporting guideline appropriate to the evaluation design.

Why report legal powers?

Authority shapes what organisations can implement, enforce and sustain.

Is planned variation a problem?

Not necessarily; it should be described and interpreted.

Does complete reporting prove policy effectiveness?

No. It makes the intervention appraisable but does not replace evaluation.

PRIMARY SOURCES

Read the original tidier_php guidance

Facts were checked against original publications and official records on 5 November 2026. Follow the live source for later corrections, completed updates or companion material.

A cheerful final note

Precise English makes describe a population policy as the system of authority, organisations and variation that delivered it more generous, not less. People can see how their evidence and values entered the work, where disagreement remains and what a responsible next step looks like.

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