As the population mean (Loeve, 1977). Stuttered and non-stuttered disfluencies–Our second finding that preschool-age CWS produce significantly more stuttered and non-stuttered disfluencies than CWNS corroborates findings from previous studies (Ambrose Yairi, 1999; Johnson et al., 1959; Yairi Ambrose, 2005). Whereas the frequency of stuttered disfluencies has been commonly used as a talker-group H 4065 web classification criterion, our data suggest that non-stuttered disfluencies could also be employed to augment decisions about talker group classification based on stuttered disfluencies. The finding that preschool-age CWS produce significantlyNIH-PA Author Manuscript NIH-PA Author Manuscript NIH-PA Author Manuscript7PNB-0408 supplier present authors recognize that syllable-level measures of stuttering can be converted to word-level measures of stuttering and vice versa (Yaruss, 2001). However, this issue goes beyond the purpose and scope of the present study. J Commun Disord. Author manuscript; available in PMC 2015 May 01.Tumanova et al.Pagemore non-stuttered disfluencies than CWNS and that the number of non-stuttered disfluencies was a significant predictor for talker group classification provides empirical support for the notion that total number of disfluencies may be another augmentative measure useful for distinguishing between children who do and do not stutter (Adams, 1977). One seemingly apparent assumption, whether children are classified according to parental report (e.g., Boey et al., 2007; Johnson et al., 1959) or objective criteria (e.g., Pellowski Conture, 2002), is that the speech disfluencies exhibited by CWS versus those of CWNS are more dimensional (i.e., continuous) than categorical (i.e., non-continuous) in nature. Our data suggests that both talker groups produce instances of stuttered disfluencies as well as speech disfluencies not classified as stuttering. Thus, the disfluency distributions for the two talker groups overlap to some degree (something earlier discussed and/or recognized by Johnson et al., 1963). This, of course, does not mean that the two groups are identical. Neither does this overlook the fact that some individuals close to the between-group classification criterion will be challenging to classify. However, clinicians and researchers alike must make decisions about who does and who does not stutter when attempting to empirically study or clinically treat such children. One attempt to inform this decision-making process or minimize behavioral overlap between the two talker groups is the establishment of a priori criteria for talker group classification (taking into consideration empirical evidence, as well as parental, caregiver and/or professional perceptions). The present finding that the number of non-stuttered disfluencies significantly predicted talker group classification support the use of that variable as an adjunct to (but certainly not replacement for) the 3 stuttered disfluencies criterion for talker group classification. It should be noted, however, that while minimizing one type of error (e.g., false negatives) this practice may increase the chances of false positives (see Conture, 2001, Fig. 1.1, for further discussion of the issue of false positives and false negatives when classifying children as CWS vs. CWNS). At present, it seems safe to say that there are no absolute, error-free demarcations that perfectly (i.e., 100 of the time) separate the two talker groups. However, as movement toward a more da.As the population mean (Loeve, 1977). Stuttered and non-stuttered disfluencies–Our second finding that preschool-age CWS produce significantly more stuttered and non-stuttered disfluencies than CWNS corroborates findings from previous studies (Ambrose Yairi, 1999; Johnson et al., 1959; Yairi Ambrose, 2005). Whereas the frequency of stuttered disfluencies has been commonly used as a talker-group classification criterion, our data suggest that non-stuttered disfluencies could also be employed to augment decisions about talker group classification based on stuttered disfluencies. The finding that preschool-age CWS produce significantlyNIH-PA Author Manuscript NIH-PA Author Manuscript NIH-PA Author Manuscript7Present authors recognize that syllable-level measures of stuttering can be converted to word-level measures of stuttering and vice versa (Yaruss, 2001). However, this issue goes beyond the purpose and scope of the present study. J Commun Disord. Author manuscript; available in PMC 2015 May 01.Tumanova et al.Pagemore non-stuttered disfluencies than CWNS and that the number of non-stuttered disfluencies was a significant predictor for talker group classification provides empirical support for the notion that total number of disfluencies may be another augmentative measure useful for distinguishing between children who do and do not stutter (Adams, 1977). One seemingly apparent assumption, whether children are classified according to parental report (e.g., Boey et al., 2007; Johnson et al., 1959) or objective criteria (e.g., Pellowski Conture, 2002), is that the speech disfluencies exhibited by CWS versus those of CWNS are more dimensional (i.e., continuous) than categorical (i.e., non-continuous) in nature. Our data suggests that both talker groups produce instances of stuttered disfluencies as well as speech disfluencies not classified as stuttering. Thus, the disfluency distributions for the two talker groups overlap to some degree (something earlier discussed and/or recognized by Johnson et al., 1963). This, of course, does not mean that the two groups are identical. Neither does this overlook the fact that some individuals close to the between-group classification criterion will be challenging to classify. However, clinicians and researchers alike must make decisions about who does and who does not stutter when attempting to empirically study or clinically treat such children. One attempt to inform this decision-making process or minimize behavioral overlap between the two talker groups is the establishment of a priori criteria for talker group classification (taking into consideration empirical evidence, as well as parental, caregiver and/or professional perceptions). The present finding that the number of non-stuttered disfluencies significantly predicted talker group classification support the use of that variable as an adjunct to (but certainly not replacement for) the 3 stuttered disfluencies criterion for talker group classification. It should be noted, however, that while minimizing one type of error (e.g., false negatives) this practice may increase the chances of false positives (see Conture, 2001, Fig. 1.1, for further discussion of the issue of false positives and false negatives when classifying children as CWS vs. CWNS). At present, it seems safe to say that there are no absolute, error-free demarcations that perfectly (i.e., 100 of the time) separate the two talker groups. However, as movement toward a more da.