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N-of-1 Trials in the Behavioral Sciences

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The Essential Guide to N-of-1 Trials in Health

Abstract

This chapter describes the application of N-of-1 trials in the behavioural sciences, where they are commonly referred to as single-case experimental designs (SCEDs). Four essential features demarcate single-case methodology from between-group designs: (i) the individual serves as his or her own control, (ii) use of a specific and operationally-defined behaviour that is targeted by the intervention, (iii) frequent and repeated measurement of the target behaviour throughout all phases of the experiment, and (iv) issues surrounding external validity. Features that strengthen internal and external validity of SCEDs are discussed in the context of a standardised scale to evaluate the scientific quality of SCEDs and N-of-1 trials, the Risk of Bias in N-of-1 Trials (RoBiNT) Scale. New work in developing a reporting guide in the CONSORT tradition (the Single-Case Reporting guideline In BEhavioural interventions, SCRIBE) is referenced. Subsequent sections in the chapter highlight differences among the prototypical single-case designs reported in the literature, both experimental (withdrawal/reversal, multiple-baseline, alternating-treatments, and changing-criterion designs) and non-experimental (biphasic A-B design, B-phase training study, pre-intervention/post-intervention design, and case description/report), along with illustrative examples reported in the literature. The final section of the chapter describes available methods to analyse data produced by SCEDs, including structured visual analysis, randomization tests and other statistical procedures.

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Notes

  1. 1.

    PsycBITE is a multi-disciplinary database that archives all of the published empirical articles on nonpharmacological treatments for the psychological consequences of acquired brain impairment and contains more than 4,500 records. Controlled studies (both group and single-case) are rated for scientific rigor and ranked on the database in terms of their scientific quality.

  2. 2.

    Autocorrelation in a series of observations refers to the degree of predictability or lack of independence between one observation and the subsequent observation. It is usually expressed as a Pearson-Product Moment Correlation coefficient between all pairs of consecutive observations.

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Author information

Authors and Affiliations

  1. John Walsh Centre for Rehabilitation Research, Kolling Institute of Medical Research, Sydney Medical School-Northern, University of Sydney, Sydney, Australia

    Robyn L. Tate

  2. Department of Neurology, Royal North Shore Hospital, Sydney, Australia

    Michael Perdices

  3. Department of Psychological Medicine, Sydney Medical School-Northern, University of Sydney, Sydney, Australia

    Michael Perdices

Authors
  1. Robyn L. Tate
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  2. Michael Perdices
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Correspondence to Robyn L. Tate .

Editor information

Editors and Affiliations

  1. School of Medicine, The University of Queensland, Ipswich, Queensland, Australia

    Jane Nikles

  2. School of Medicine, The University of Queensland, Ipswich, Queensland, Australia

    Geoffrey Mitchell

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Tate, R.L., Perdices, M. (2015). N-of-1 Trials in the Behavioral Sciences. In: Nikles, J., Mitchell, G. (eds) The Essential Guide to N-of-1 Trials in Health. Springer, Dordrecht. https://doi.org/10.1007/978-94-017-7200-6_3

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