title: Event- and interval-based measurement of stuttering: a review.
abstract: BACKGROUND
  Event- and interval-based measurements are two different ways of computing frequency of stuttering. Interval-based methodology emerged as an alternative measure to overcome problems associated with reproducibility in the event-based methodology. No review has been made to study the effect of methodological factors in interval-based absolute reliability data or to compute the agreement between the two methodologies in terms of inter-judge, intra-judge and accuracy (i.e., correspondence between raters' scores and an established criterion).
  
  
  OBJECTIVE
  To provide a review related to reproducibility of event-based and time-interval measurement, and to verify the effect of methodological factors (training, experience, interval duration, sample presentation order and judgment conditions) on agreement of time-interval measurement; in addition, to determine if it is possible to quantify the agreement between the two methodologies
  
  
  METHODS
  The first two authors searched for articles on ERIC, MEDLINE, PubMed, B-on, CENTRAL and Dissertation Abstracts during January-February 2013 and retrieved 495 articles. Forty-eight articles were selected for review. Content tables were constructed with the main findings.
  
  
  RESULTS
  Articles related to event-based measurements revealed values of inter- and intra-judge greater than 0.70 and agreement percentages beyond 80%. The articles related to time-interval measures revealed that, in general, judges with more experience with stuttering presented significantly higher levels of intra- and inter-judge agreement. Inter- and intra-judge values were beyond the references for high reproducibility values for both methodologies. Accuracy (regarding the closeness of raters' judgements with an established criterion), intra- and inter-judge agreement were higher for trained groups when compared with non-trained groups. Sample presentation order and audio/video conditions did not result in differences in inter- or intra-judge results. A duration of 5 s for an interval appears to be an acceptable agreement. Explanation for high reproducibility values as well as parameter choice to report those data are discussed.
  
  
  CONCLUSIONS
  Both interval- and event-based methodologies used trained or experienced judges for inter- and intra-judge determination and data were beyond the references for good reproducibility values. Inter- and intra-judge values were reported in different metric scales among event- and interval-based methods studies, making it unfeasible to quantify the agreement between the two methods.
authors.affiliation: Institute of Electronics and Informatics Engineering of Aveiro (IEETA), University of Aveiro, Aveiro, Portugal; Department of Education (DE), University of Aveiro, Aveiro, Portugal.
authors.forename: Ana Rita S
authors.initials: AR
authors.lastname: Valente
authors.forename: Luis M T
authors.initials: LM
authors.lastname: Jesus
authors.forename: Andreia
authors.initials: A
authors.lastname: Hall
authors.forename: Margaret
authors.initials: M
authors.lastname: Leahy
mesh_terms: D001521:Behavior Therapy / Q000379:methods; D002648:Child; D006801:Humans; D015588:Observer Variation; D015203:Reproducibility of Results; D013068:Speech Production Measurement / Q000379:methods* / Q000706:statistics & numerical data; D013070:Speech Therapy / Q000379:methods; D013342:Stuttering / Q000145:classification* / Q000175:diagnosis* / Q000628:therapy
keywords: accuracy; event-based measurement; inter-judge; interval-based measurement; intra-judge; stuttering