Preface

Purpose: The purpose of this book is to enable allied health professional (AHPs) students, clinicians, educators, researchers' and managers to understand the complex art and science of assessment and outcome measurement processes.

Who Is This Book For?

For students, the book will introduce you to the process and purpose of assessment and outcome measurement for practice, research, and service evaluation; help you to understand levels of measurement, standardisation, and psychometric properties and help you to apply this knowledge to appraise and select the best assessments and outcome measures.

For educators, the book will assist in exploring with students the purpose and importance of assessment and outcome measurement, standardisation and psycho-metrics, key aspects of test development, and the reasoning required to select and apply assessments and measures in practice.

For practitioners, the book will familiarise you with assessment and outcome measure terminology and enable you to identify the properties of tests in order to select and confidently implement appropriate standardised tests and outcome measures in your practice, service evaluation, service development, and research.

For researchers, the book will assist you in developing a new assessment or outcome measure; creating a culturally sensitive version of an existing measure; undertaking a linguistically valid translation of a measure published in another language; collecting normative data; conducting psychometric studies to examine aspects of validity and reliability; and/or exploring the face validity or clinical utility of a measure.

For managers, the book will assist in identifying the importance of assessment and outcome measures for service evaluation and improvement, and to select and measure outcomes as required by commissioners and senior managers.

How Is This 2nd Edition Structured?

In this 2nd edition, there are a number of changes to enable you to locate the information you require for different aspects of assessment and outcome measurement, such as choice, development, and utilisation. The book is divided into four sections. The following pages provide a brief description of each section and the related chapters. Each chapter will start with key words, a chapter overview, and review questions.

Signposts are provided to help you to navigate to what you need and want to know. Worksheets are embedded in the relevant chapters for you to use on your own or for group learning. There are worksheets with relevance for students, clinicians, researchers, and/or managers. A completed worksheet could be used within your Continuing Professional Development portfolio as part of your evidence of learning and development, e.g. in the United Kingdom (UK) for Health and Care Professions Council (HCPC) registration requirements. Throughout the book, examples of standardised tests along with clinical examples, case vignettes, and case histories are used to help you see how to apply the principles and skills described in your practice, research, and/or service evaluation. Review questions and brief answers are provided to help you check whether you have understood the key concepts from each chapter.

Section 1: Assessment and Measurement in Practice

Chapter 1 focuses on the importance of accurate assessment in practice. Chapter 2 describes methods of assessment (including the advantages and disadvantages of informal versus standardised methods) such as self-report, proxy, and observational approaches. In Chapter 3, the different purposes of assessment in practice (such as descriptive, discriminative, predictive, and evaluative) are explored, and the timing of assessments (including initial, baseline, monitoring, and outcome) are considered. Chapter 4 addresses the question of 'what is measurement?' and provides definitions and examples of four levels of measurement (nominal, ordinal, interval, and ratio). Chapter 5 explains the process of test administration and makes suggestions for reporting and recording test results. Chapter 6 explains the importance of clinical reasoning and reflective practice in effective assessment and discusses different types of clinical reasoning (including diagnostic, interactive, pragmatic, procedural, narrative, and ethical reasoning).

Section 2: Concepts for Assessment and Measurement

Chapter 7 examines the importance of standardisation in research and the role of norm-referenced and criterion-referenced tests. Chapter 8 focuses on the topic of validity and concludes with an exploration of face validity and clinical utility. Chapter 9 examines reliability, including an explanation of the different types of reliability, statistics used to examine levels of reliability, and concepts such as responsiveness, test specificity, sensitivity, error of measurement, and floor or ceiling effects. Chapter 10 explains how to find, select, and critically appraise assessment and outcome measurements, along with a detailed example of a test critique.

Section 3: Assessment and Measurement for Service Evaluation and Improvement

Chapter 11 explores the application of models of function to AHP assessment and measurement, illustrated with several examples, including the World Health Organisation's (2002) International Classification of Functioning, Disability and Health. Chapter 12 gives advice on implementing the optimum assessment and measurement approach for your practice or service. Chapter 13 considers how to use assessment and outcome measures for evaluating your assessment practice, undertaking a service evaluation' and planning improvements to your assessment process.

Section 4: Developing and Evaluating Assessments and Outcome Measures

Chapter 14 explores test development, in particular, what to consider when developing a new test or undertaking additional work on an existing measure such as to improve cultural sensitivity or to translate it into another language. Chapter 15 explores methodology for examining different psychometric properties of measures.

As we were considering the structure and format for this new edition of the book, we had the opportunity to lead two professional Twitter dialogues through #OTalk (https://twitter.com/OTalk_). The first Twitter dialogue focussed on 'Assessment and Outcome Measures' (19 February 2019), and we thank the 40 participants in the chat for an engaging and fast-paced one-hour discussion with 400 tweets. The second was on 'Why Aren't All Therapists Using Standardised Assessments Routinely in Practice?' (21 May 2019), and we thank the 42 participants in that chat for an interesting and informative discussion with 515 tweets.

Table 1 highlights the recurring themes, and related needs and requirements, identified by participants in the Twitter chat. These themes, although predominantly drawn from occupational therapists, echo those identified within the literature by other AHPs, and we felt it would be useful to share them in this preface.

The participants' questions and recommendations about assessment are listed below and have been incorporated, as appropriate, throughout the book.

• Think
  • What do you need to know?
  • What is causing the person's problem?
• What assessment tool will measure the person's difficulties?
• What influences your choice of assessment or outcome measure?
• Select an assessment that is the most suitable and reliable for the needs of the individual.
• Be clear that you may need more than one assessment to consider a range of difficulties.
• Do not modify or 'tweak' the assessment, as it is no longer valid.
• Informal interviews and observations may help you build a rapport with the person; however, you need to be able to demonstrate therapy outcomes through your assessment and measures.
• Gain an understanding of the measure, consider how it was validated, and with which client groups.
• Learn how to administer, score, and interpret results. This can require time.
• Make use of supervision and peer support. Reflect, discuss, evaluate, and learn about a range of assessments. Practise by assessing your peer group.
• Balance demonstration of outcomes for commissioners and having quality interaction to demonstrate person-centred care.
• Have a 'go to' resource to identify appropriate assessment and measures such as Asher's book (2014) and McDowell's (2006).

Alison J. Laver-Fawcett and Diane L. Cox (March 2021).

TABLE 1 Assessment and outcome measures themes and requirements (@OTalk, Feb 2019).