Module 13-14 Review Epidemiology Methods

IMRad Structure

Introduction, Methods, Results, and Discussion

Follow a predictable change in focus.

Start introduction: context of the research (broad focus)

End introduction: research question/Aim (narrow focus)

Methods: Research methods used (narrow focus)

Results: Research results (narrow focus)

Start discussion: discussion of research results (narrow focus)

End discussion: Implications of research results (broad focus)

Reporting guidelines

provide input on what to report in each section of the paper. The goal is to promote transparent and accurate reporting.

Reporting guidelines of Randomized control trials

CONSORT

Reporting guidelines of Cohort, Case control, and Cross-sectional studies

STROBE

Other Components that do not fall under IMRaD

-Title

-Authors and author information

-Abstract

-Keywords

-Acknowledgements

-Funding Details

-Reference list

-Supplementary materials

Title

communicates the central research questions and functions as advertisement for potential readers.

Authors and author information

The authors’ names and affiliations are typically listed below the title. Typically, one author is marked as the corresponding author: this person can be emailed by the readers in case of questions. Author sequence is typically effort based.

Authorship criteria

1. Substantial contributions to the conception of the design of the work; or the acquisition, analysis, or interpretation of data for the WORK and

2. Drafting the work or reviewing it critically and important intellectual content

3. Final approval of the version to be published

4. Agreement to be accountable for all aspects of the work ensuring that questions are related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

Keywords

Typically 5 keywords are listed on the first page and used for indexing databases.

Acknowledgements

Recognition of individuals who contributed to the study but did not fulfill the authorship criteria.

Supplementary materials

Any results and or methodology that is secondary to the aim of the study can be included in supplementary materials.

Goals of introduction

Provide the context of the research

Describe the gap that the research aims to fill.

Introduce the research question/aim.

They start broad and then narrow focus.

Component 1: Context of the Research (Introduction)

Starts with the broadest context of the work to establish the importance of the research. This is followed by information on the current state of the literature on the specific subtopic on which the study is focused.

Component 2: Gap in the Existing Literature (introduction)

Gap can take various forms:

existing gap in the literature

a contradiction to the existing literature

limitations of the previous studies.

Component 3: Focus on the current study

The research question/aim of the study

Pre-specified hypotheses regarding the research questions.

A brief description of the approach used to address the aim.

Goals of the Methods section

Describes the procedures used for data collection

Describes how variables are measured

Describes how data were analyzed.

Has a narrow focus throughout

Component 1: Study population and design (Methods)

The key elements of the study design including intended sample size.

The settings, locations, and relevant dates:

The period of recruitment

The follow-up

Data collection

The in and exclusion criteria used for recruitment of the participants.

component 2: definitions and measurements of variables (methods)

Definitions of the variables of interest (exposure, outcome, and confounders)

Method used to collect the data of each variable (name of the questionnaire)

Any manipulations to the variables after data collection (eg categorization)

Typically, subsections are used for each type of variable (exposure, outcome, and confounders).

component 3: statistical analyses

Statistical methods are used to describe the study sample.

Statistical methods are used to estimate the effects of interest.

This includes methods to minimizing confounding, assess effect modification, address missing data, and address loss to follow-up.

Bias minimization

Efforts to minimize bias (information bias, selection bias, and confounding bias) are also described in the methods section.

These efforts are described throughout the methods section and can be design based, or analysis based.

Goals of the results section

Describes the study sample

Report the effect estimates

has a narrow focus throughout

Component 1: description of the study sample (results)

Description of the number of participants at each stage of the study.

Eligible: potentially eligible and confirmed eligible.

Included at baseline.

Typically reported both in-text and in flow diagram.

Descriptive statistics are reported for all variables used in the analyses including means and standard deviation for continuous variables, and numbers of percentages for binary variables.

They are typically reported both in-text and in Table 1.

Component 2: Effect estimates

Estimates the effects of interest, including 95% confidence intervals. Often unadjusted and confounder adjusted effect estimates are reported. Effect estimates are typically reported both in-text and tables.

Goals of discussion section

Provides an answer to the research question.

Compare and contrast results with previous studies.

Lists strengths and limitations of the study.

Component 1: Summary of Key findings (Discussion)

Answer to the research question.

Interpretation of effect estimates in the broader context: the implications of the findings for the research field.

Component 2: comparison of results with previous studies (Discussion)

Comparison and contrasting of the results with results from previous studies.

Explanation of reasons similar/different results compared with previous studies.

Component 3: Discussion of possible mechanisms (Discussion)

Possible explanation for the observed effect mechanisms.

Component 4: Discussion of the study limitations (Discussion)

If remaining biases are likely how may this have impacted the effect estimates. Often future directions are provided.

Component 5: Discussion on the generalizability of the findings (

Discussion of the extent to which the findings hold for the population from which the participants were sampled.

Component 6: Conclusion

Typically reiterates the key findings, the implication of the findings for the field.

Direction for future research .

Goals of the abstract

Communicate the main objective, methods, results, and conclusion.

Provides a summary of the study (approximately 200 words)

Needs to be self contained and does not contain references.

Structure of an abstract

follows a mini-IMRaD structure:

Introductions/background/aim

Methods/approach

Results

Conclusions

Structured abstracts include subheaders, unstructured abstracts do not.

Paragraphs

The most obvious unit within subsections of scientific papers. Often easily recognized due to indentations or white spaces between paragraphs.

Paragraph focus

Focuses on only one topic only

A well written paragraph is unified: all sentences in the paragraph relate to the same topic

Coherent: the sentence describes the topic in a logical order, relating one sentence to the next.

Distinct: the paragraph can be understood on its own.

Paragraph structure

1. Topic sentence: introduces the central topic of the paragraph.

2. Supporting sentences: elaboration on the central topic.

3. Concluding sentence: summarizes the information provided in the paragraph.

Linking paragraphs

Paragraphs within a section need to relate to one another in a logical way to create a coherent section.

Techniques to link paragraphs within a section include:

Logical arrangement of paragraphs within sections.

Repetition of key words

Use of transitional expressions

Sentence structure

1. A subject: the subject undertaking the action

2. A verb: the action

3. An object: the object receiving the action.

Tense and voice

Tense: places the action in the past, present, or future.

Voice: active voice versus passive voice.

Past tense

1. Simple past: duration of the action is not important (we performed a study)

2. Past progressive: action was ongoing through time (we were performing a study)

3. Past perfect: completed action (we had performed a study)

4. Past perfect progressive combines the past progressive and past perfect (we had been performing a study)

Simple future tense

1. Simple future: duration of action is not important (we will perform a study)

2. Future progressive: action will be ongoing through time (we will be performing a study)

3. Future perfect: completed action (we will have performed a study)

4. Future perfect progressive: combines future progressive and future perfect.

Tenses in epidemiological papers

Introduction: combination of past, present, and future tenses.

Methods: past tense.

Results: past tense

Discussion: combination of past, present, and future tenses.

sentence voice

Passive voice: is often used to increase the sense of objectivity

Active voice: can help achieve clear communication

Active voice versus passive voice

Active voice: We (subject) performed (verb) a study (object)

Passive voice: A study (subject) was performed (verb).

Reasons to use active voice

It is short: typically sentences are shorter in an active voice than in a passive voice.

It is easier to read: active voice is more commonly used in everyday reading.

It is engaging: readers relate easier to sentences with human subjects

Reasons to use passive voice

To direct attention: the subject is emphasized

To obscure the actor: when the actor is irrelevant.

Topic and stress positions

Topic position: the first few words of of a sentence

Stress position: the last few words of a sentence.

Long words

When multiple words have the same meaning the short words are preferred.

Use instead of utilize

Show instead of demonstrate

Studied instead of investigated.

Jargon

Can be effective when the aim is to be precise.

Jargon decreases readability when:

Simpler alternative terms exist.

When the audience is not familiar with jargon.

Using the Jargon effectively

Jargon can be used when precision is needed.

If possible use simpler terms elsewhere.

Eg. define dementia as “vascular dementia: in the methods section but using the term dementia in the remainder of the paper.

Abbreviations

are often used to reduce the number of words.

Often used abbreviations (BMI and DNA) can help improve readability.

Abbreviations can decrease readability when: They are new/less familiar to the reader.

Many abbreviations are used.

Only abbreviate terms if they reappear in the text.

Nominalization

Are nouns built from verbs

We conducted an analysis (noun) of data

We analyzed (verb) the data’

Nominalization lengthen the text and decrease readability.