David Bowers - Understanding Clinical Papers

1 Cover

2 Title Page Understanding Clinical Papers Fourth Edition David Bowers Leeds Institute of Health Sciences, School of Medicine, University of Leeds, UK Allan House Leeds Institute of Health Sciences, School of Medicine, University of Leeds, UK David Owens Leeds Institute of Health Sciences, School of Medicine, University of Leeds, UK Bridgette Bewick Leeds Institute of Health Sciences, School of Medicine, University of Leeds, UK

3 Copyright Page

4 Preface to the First Edition

5 Preface to the Second Edition SOME NOTES ON STATISTICAL SOFTWARE WRITING PAPERS FOR CLINICAL JOURNALS

6 Preface to the Third Edition

7 Preface to the Fourth Edition

8 PART I: Setting the Scene: Who Did What, and Why CHAPTER 1: Some Preliminaries WHO WROTE THE PAPER? IN WHAT SORT OF JOURNAL DOES THE PAPER APPEAR? WHO (AND WHAT) IS ACKNOWLEDGED? CHAPTER 2: The Abstract and Introduction THE ABSTRACT THE INTRODUCTION ETHICAL CONSIDERATIONS CHAPTER 3: The Aims and Objectives HYPOTHESES OBJECTIVES THAT ARE NOT HYPOTHESIS TESTING STUDIES WITH UNCLEAR OBJECTIVES

9 PART II: Design Matters: What Type of Study Is It? CHAPTER 4: Descriptive Studies QUALITATIVE RESEARCH TYPES OF QUALITATIVE STUDY CHAPTER 5: Descriptive Studies CASE REPORTS CASE SERIES CROSS‐SECTIONAL STUDIES LONGITUDINAL STUDIES CHAPTER 6: Analytic Studies ECOLOGICAL STUDIES CROSS‐SECTIONAL, TWO‐GROUP STUDIES CASE–CONTROL STUDIES COHORT ANALYTIC STUDIES VARIATIONS IN CASE–CONTROL AND COHORT DESIGNS COMPARING AND CONTRASTING CASE–CONTROL AND COHORT STUDIES ‘STROBE' GUIDELINES CHAPTER 7: Intervention Studies TRIALS RANDOM ALLOCATION AND ITS CONCEALMENT CONSENT AND RANDOMIZATION IN TRIALS PLACEBOS OR TREATMENT‐AS‐USUAL PRAGMATIC AND EXPLANATORY TRIALS INTENTION‐TO‐TREAT ANALYSIS FEASIBILITY AND PILOT STUDIES CLUSTER RANDOMIZED TRIALS ADAPTIVE TRIAL DESIGN CONSORT GUIDELINES CHAPTER 8: Mixed Methods Research CHAPTER 9: Studies of Complex Interventions CHAPTER 10: Systematic Review and Meta‐Analysis SYSTEMATIC REVIEW PUBLICATION AND OTHER BIASES THE FUNNEL PLOT HETEROGENEITY COMBINING THE STUDIES ‘PRISMA' GUIDELINES SYSTEMATIC REVIEW OF NON‐TRIALS RESEARCH CHAPTER 11: Systematic Review of Qualitative Studies

10 PART III: The Cast: Finding Out About the Subjects of the Research CHAPTER 12: The Research Setting CHAPTER 13: Populations and Samples in Quantitative Research SAMPLING SAMPLE SIZE AND POWER CHAPTER 14: Research Using Already‐Collected Data SOURCES OF ALREADY‐COLLECTED DATA PROBLEMS WITH ALREADY‐COLLECTED DATA MISSING DATA IN ALREADY‐COLLECTED DATASETS CONFOUNDING IN ALREADY‐COLLECTED DATA CHAPTER 15: The Sample in Qualitative Research THE NATURE OF SAMPLES IN QUALITATIVE RESEARCH SAMPLE SIZE IN QUALITATIVE RESEARCH SAMPLING FOR QUALITATIVE RESEARCH CHAPTER 16: Identifying and Defining Cases CHAPTER 17: Controls and Comparisons

11 PART IV: Establishing the Facts: Starting with Basic Observations CHAPTER 18: Identifying the Characteristics of Quantitative Data TYPES OF VARIABLE – TYPES OF DATA IDENTIFYING DATA TYPE SHAPES OF DISTRIBUTIONS CHAPTER 19: Summarizing the Characteristics of Quantitative Data SUMMARY MEASURES OF LOCATION SUMMARY MEASURES OF SPREAD CHAPTER 20: Identifying and Summarising the Characteristics of Qualitative Data CHAPTER 21: Measuring the Characteristics of Participants INFORMATION AND MEASUREMENT BIAS BIAS ARISING FROM MISSING VALUES CHAPTER 22: Measuring the Characteristics of Participants CHAPTER 23: Diagnostic Tests THE MEASURES THE SENSITIVITY VERSUS SPECIFICITY TRADE‐OFF – THE RECEIVER OPERATING CHARACTERISTIC (ROC) CURVE CHAPTER 24: Measurement Scales THE MEASUREMENT PROBLEM WHAT ARE MEASUREMENT SCALES? WHEN AUTHORS USE DATA FROM MEASUREMENT SCALES DEVELOPMENT OF A NEW MEASUREMENT SCALE SCALE CONSTRUCTION DESIRABLE PROPERTIES OF SCALES CHAPTER 25: Exploring and Explaining

12 PART V: Establishing More of the Facts: Some Common Ways of Describing Results CHAPTER 26: Fractions, Proportions, and Rates CHAPTER 27: Risks and Odds RISK ODDS CHAPTER 28: Ratios of Risks and OddsRISK RATIO ODDS RATIO CLINICAL TRIALS AND ‘NUMBERS NEEDED TO TREAT'

13 PART VI: Analysing the Data: Estimation and Hypothesis Testing CHAPTER 29: Confidence Intervals for Means, Proportions, and Medians WHAT IS A CONFIDENCE INTERVAL? CONFIDENCE INTERVALS FOR DIFFERENCES IN TWO MEANS CONFIDENCE INTERVALS AND CLINICAL EFFECTIVENESS CONFIDENCE INTERVALS FOR DIFFERENCES IN TWO PERCENTAGES CONFIDENCE INTERVALS FOR DIFFERENCES IN TWO MEDIANS CHAPTER 30: Confidence Intervals for Ratios CONFIDENCE INTERVALS FOR ODDS RATIOS CONFIDENCE INTERVALS FOR RISK RATIOS CONFIDENCE INTERVALS FOR HAZARD RATIOS CHAPTER 31: Testing Hypotheses – The p ‐value ASSESSING THE EVIDENCE AGAINST THE HYPOTHESIS – THE P ‐VALUE MAKING THE WRONG DECISION – TYPES OF ERROR HYPOTHESIS TESTS AND CONFIDENCE INTERVALS COMPARED TWO‐TAILED VERSUS ONE‐TAILED TESTS MATCHED VERSUS INDEPENDENT GROUPS TRANSFORMING DATA FINALLY

14 PART VII: Analysing the Data: Multivariable Methods CHAPTER 32: Measuring Association MEASURING ASSOCIATION THE CORRELATION COEFFICIENT CHAPTER 33: Measuring Agreement MEASURING AGREEMENT WITH NOMINAL DATA INTERPRETING κ AGREEMENT WITH ORDINAL DATA: WEIGHTED κ MEASURING AGREEMENT WITH METRIC DATA CHAPTER 34: Linear RegressionWHY REGRESSION? LINEAR REGRESSION ESTIMATING THE REGRESSION COEFFICIENTS – ORDINARY LEAST SQUARES ESTIMATION MEASURING THE STATISTICAL SIGNIFICANCE OF THE REGRESSION PARAMETERS MODEL‐BUILDING AND VARIABLE SELECTION AUTOMATED (OR STEPWISE) VARIABLE SELECTION MANUAL VARIABLE SELECTION METHODS INTERPRETING THE REGRESSION COEFFICIENTS GOODNESS‐OF‐FIT DUMMY (OR DESIGN) VARIABLES TESTING THE ASSUMPTIONS OF THE LINEAR REGRESSION MODEL EFFECT MODIFICATION AND INTERACTION SUMMARY ANALYSIS OF VARIANCE (ANOVA) MULTIVARIATE STATISTICS CHAPTER 35: Logistic Regression THE LOGISTIC REGRESSION MODEL VARIABLE SELECTION AND MODEL ESTIMATION INTERPRETATION AND STATISTICAL SIGNIFICANCE OF THE REGRESSION COEFFICIENTS DUMMY VARIABLES GOODNESS‐OF‐FIT EFFECT MODIFICATION – INTERACTION MODEL DIAGNOSTICS CHAPTER 36: Poisson RegressionPREAMBLE POISSON REGRESSION GOODNESS‐OF‐FIT ZERO‐INFLATED POISSON REGRESSION NEGATIVE BINOMIAL REGRESSION ZERO‐INFLATED NEGATIVE BINOMIAL REGRESSION (ZNIB) CHAPTER 37: Measuring Survival THE KAPLAN–MEIER METHOD – MEDIAN SURVIVAL TIME THE LOG‐RANK TEST LOG‐RANK TEST FOR TREND THE PROPORTIONAL HAZARDS (OR COX'S) REGRESSION MODEL CHAPTER 38: Analysing Qualitative Data

15 PART VIII: Reading Between the Lines: How Authors use Text, Tables, and Pictures to Tell You the Story CHAPTER 39: Results in Text and TablesRAW RESULTS AND COOKED FINDINGS INTERESTING FINDINGS LEGENDS AND BRACKETS DASHES CHAPTER 40: Results in PicturesWHY USE CHARTS AND FIGURES? SHAPE OF DISTRIBUTIONS CHAPTER 41: The Discussion and Conclusions

16 References

17 Index

18 End User License Agreement

1 Chapter 31Table 31.1 A few of the more common statistical tests.

1 Chapter 1 Figure 1.1 Authors and research centres listed at the start of a research pa... Figure 1.2 Paper written by multiple authors on behalf of several research g... Figure 1.3 Acknowledgement of statistical, financial, and other support at t...

2 Chapter 2 Figure 2.1 An example of a structured Abstract – this one from a trial of tw... Figure 2.2 An unstructured Abstract accompanied by a list of Keywords indica... Figure 2.3 Explaining the background to a research study. Figure 2.4 Introduction explaining the rationale for the study. Figure 2.5 Ethical considerations in a study involving adults with a learnin...

3 Chapter 3 Figure 3.1 Statement of a study's main hypothesis. Figure 3.2 A study with two hypotheses. Figure 3.3 The (structured) Abstract of a qualitative study, starting with a... Figure 3.4 The aim of the qualitative study. Figure 3.5 New subgroup analysis in report of an RCT.