Poore & Ferguson (2008)


Comparison Research


NOTE: No summary of intervention is included in the review because the investigation does not involve therapy.


 eta =   partial eta squared

f = female

fo = Fundamental frequency

m = male

MLU = mean length of utterance

NA = Not Applicable

P = participant or patient

pmh = Patricia Hargrove, blog developer

SLP = speech-language pathologist



SOURCE: Poore, M. A., & Ferguson, S. H. (2008.) Methodological variables in choral reading. Clinical Linguistics & Phonetics, 22 (1), 13-24.




DATE: November 4, 2016


ASSIGNED GRADE FOR OVERALL QUALITY: Not graded because this was not an intervention study; nevertheless, it does have clinical implications.


TAKE AWAY: The investigators explored prosody of typical adults in a variety of reading contexts (3 scripts and 3 reading conditions.) Compared to Solo reading, Choral reading resulted in smaller fundamental frequency (fo) variability, smaller amplitude variability, and smaller vowel duration variability. Track reading (i.e., in unison with prerecorded scripts) resulted in significantly more vowel errors, suggesting that Track reading might not be a feasible alternative to Choral reading.



  1. What type of evidence was identified?


  • What was the type of design? Prospective Single Group Experiment (exposed to Mmultiple conditions)


  • What was the focus of the research? Clinically Related


  • What was the level of support associated with the type of evidence? Level = C+



  1. Group membership determination:


  • If there were groups, were participants randomly assigned to groups? Not Applicable (NA), there was only one group.



  1. Were experimental conditions concealed?


  • from participants? No


  • from administrators of experimental conditions? No


  • from analyzers/judges? Unclear



  1. Were the groups adequately described? Yes


–   How many participants were involved in the study?


  • total # of Ps:  22 Ps (11 pairs) were in the original group. See question about maintenance below for description of loss of participants (Ps.)
  • # of groups: 1
  • Did the group maintain membership throughout the investigation? No, 6 of the pairs (i.e., 12 Ps) were eliminated from the investigation due to recording and/or interference issues at the time of the recording. Therefore, there were only 5 pairs of Ps resulting in 10 Ps.



  • age:

     – original group: 18 to 25 years

– final group: not reported

  • gender:

     – original group: 8m; 14f

– final group: 4m; 6f:

  • dialect: South Midland Dialect of American English
  • communication skills: No history of speech, language, or hearing disorders; investigator judged speech to be typical


Were the groups similar? NA


– Were the communication problems adequately described? Yes

  • disorder type: NA, communication skills of all Ps were within normal limits



  1. What were the different conditions for this research?


  • Subject (Classification) Groups?


  • Experimental Conditions? Yes

– type of reading material: poetry, fiction, textbook

– reading condition: solo, track, choral


  • Criterion/Descriptive Conditions? No



  1. Were the groups controlled acceptably? NA, there was only one group.



  1. Were dependent measures appropriate and meaningful? Yes


The dependent measures were


  • OUTCOME #1: Fundamental frequency (fo) variability
  • OUTCOME #2: Amplitude variability
  • OUTCOME #3: Vowel duration
  • OUTCOME #4: Number of vowel errors


– Outcome #4 (Number of vowel errors) was subjective.


Three of the outcomes (see below) were objective:

  • OUTCOME #1: Fundamental frequency (fo) variability
  • OUTCOME #2: Amplitude variability
  • OUTCOME #3: Vowel duration



  1. Were reliability measures provided?


– Interobserver for analyzers? No


– Intraobserver for analyzers? Yes


  • OUTCOME #3: Vowel duration- Because the measurement of vowel duration required judgment on the part of the analyzers, the investigators provided intraobserver reliability data. The correlation for remeasured vowels was 0.95


– Treatment or test administration fidelity for investigators? No



  1. Description of design:


  • Although 22 Ps (11 pairs) initially participated in the investigation, only the data from 10 Ps were analyzed due to technical issues with the recordings.


  • All reading were recorded.


  • Pairs of Ps elicited the samples by reading scripts in the following order:

– Each speaker in the pair was directed to read silently the 3 scripts (poetry, nonfiction, textbook.) The order of the scripts was counterbalanced.

– First: Solo reading of all designated scripts alone. While separated from his/her experimental partner, each P read his/her scripts alone.

– Second and Third: The order of Track and Choral readings were counterbalanced.

  • TRACK READINIG: Using his/her partner’s Solo reading script as stimuli, P read aloud his/her scripts in unison with the recorded readings of his/her experimental partner.
  • CHORAL READINIG: P read aloud his scripts in unison with the live reading of the same scripts with his/her experimental partner.


  • Some data were removed from the investigation:

– Potential outliers were identified for fo variability by highlighting

  • fo more than 2 standard deviations (SD) from the mean

     – The potential outliers were then inspected. If a fo was not continuous with the upper and/or lower limits of the P’s range, it was removed.



  1. What were the results of the statistical (inferential) testing?


– Comparisons that were significant (e.g., p ≤ 0.05):


  • OUTCOME #1: Fundamental frequency (fo) variability

– fo was significantly more variable in the solo condition

– script type, gender, gender pair, interactions were not associated with significant fo variability


  • OUTCOME #2: Amplitude variability

– Amplitude variability was significantly smaller for choral reading compared to solo and track reading

– script type and interactions were not associated with significant amplitude variability


  • OUTCOME #3: Vowel duration variability

– Differences among the 3 reading conditions were significantly different

– order of variability from most to least: track, solo, choral


  • OUTCOME #4: Number of vowel errors

     – The track condition was associated with significantly more errors than the other 2 conditions.


– What was the statistical test used to determine significance? ANOVA


– Were effect sizes provided? Yes, for some, but not all, comparisons..


  • OUTCOME #1: Fundamental frequency (fo) variability;

– Solo condition most variable; eta = 0.83 (strong)


  • OUTCOME #2: Amplitude variability

– Amplitude variability least variable in choral reading; eta = 0.73 (strong)


  • OUTCOME #3: Vowel duration variability

– Order of variability from most to least: track, solo, choral; eta = 0. 69 (strong)


– Were confidence interval (CI) provided? No



  1. Summary of correlational results:  NA



  1. Summary of descriptive results: Qualitative research NA (this item is completed only when the investigation was solely or primarily Qualitative in nature.)



  1. Brief summary of clinically relevant results:


  • The fo variability, amplitude variability, vowel duration variability, and vowel errors did not differ in the 3 types of script (poetry, nonfiction, textbook.) The investigators suggested this could be associated with the small N.


  • Choral reading appeared to be associated with

– smaller fo variability

– smaller amplitude variability

– smaller vowel duration variability


  • Track reading often differed from the other conditions in fo variability and vowel duration variability. Moreover, significantly more errors were noted in the track condition.



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