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Our purpose was to study the frequency of behavioral-emotional problems among children identified with a learning disability (LD). The data were obtained for 579 Finnish children (8-15 years) with reading disability (RD-only), math disability (MD-only), or both (RDMD) assessed at a specialized clinic between 1985 and 2017. We analyzed percentages of children with behavioral-emotional symptoms reaching clinical range (i.e., z score [greater than or equal to]1.5 SDs) and the effects of the LD type, gender, and context (home vs. school) on them. Furthermore, we analyzed the effect of the severity of LD and gender on the amount of behavioral-emotional symptoms reported by teachers and parents. Alarmingly high percentages of children, irrespective of LD type, demonstrated behavioral-emotional problems: more than 37% in Affective, Anxiety, and Attention-Deficit/Hyperactivity Disorder (ADHD) problems. Contextual variation was large, as more problems were reported by teachers than by mothers. The unique effects of gender and LD type were rare, but the results raised concern for those with MD-only, especially boys. The results underscore the need to draw attention to the importance of assessing children with LD for behavioral-emotional problems and emphasize the importance of teachers' awareness of behavioral-emotional problems among students with LD and cooperation among child, teacher, and parents in assessment and support planning.

Previous research supports the CBCL/1½--5's "DSM"-ASD scale (and its precursor, the "DSM"-PDP scale) as a Level 1 ASD screener. Confirmatory factor analyses (CFAs) with data from population samples in 24 societies (N = 19,850) indicated good measurement invariance across societies, especially for configural and metric invariance. Items 4. 25, 67, 80, and 98 may be especially good discriminators of ASD because they have tend to have low base rates, strong loadings on the ASD latent construct, and the best measurement invariance across societies. Further research is needed to test the discriminative power of these items in predicting ASD, but our strong measurement findings support the international psychometric robustness of the CBCL/1½--5's "DSM"-ASD scale. [This article was co-written by the International Achenbach System of Empirically Based Assessment (ASEBA) Consortium.]

There are few studies of behavior problems in preterm children prior to 2 years old and the changes that occur over time. The aims of this study were to examine the patterns and prediction of behavior problems and the effects of gender and socioeconomic status (SES) on behavior problems in preterm children at the toddler and preschool periods. Parents of 124 very low birthweight preterm children completed a standardized behavior questionnaire at 18 months corrected age and 3 years old. At both times, scores were significantly higher on Attention and Withdrawn Problems than on other behavior problem syndromes. There was a significant overall increase in Externalizing and Internalizing behavior problem scores between 18 months and 3 years, particularly in Internalizing problems. Overall prediction for normal versus not-normal categorization ([greater than or equal to]1 standard deviation) on behavior problem and broad-spectrum scales ranged from 77% to 90% and was higher for children in the normal than not-normal categories. Boys had higher Internalizing Problems at 18 months and higher Externalizing Problems at 3 years. Children from low SES families had higher Internalizing and Total Behavior problems at 18 months and higher Internalizing, Externalizing, and Total Behavior problems at 3 years. Screening preterm children for behavior problems before 2 years old appears useful for early intervention of such problems.

This study tested international similarities and differences in scores on a scale comprising 12 items identified by international mental health experts as being very consistent with the "Diagnostic and Statistical Manual of Mental Disorders" (5th ed.) category of autism spectrum disorder. Participants were 19,850 preschoolers in 24 societies rated by parents on the Child Behavior Checklist for Ages 1½-5; 10,521 preschoolers from 15 societies rated by caregivers/teachers on the Caregiver--Teacher Report Form, and 7380 children from 13 societies rated by both types of informant. Rank ordering of the items with respect to base rates and mean ratings was more similar across societies for parent ratings than caregiver/teacher ratings, especially with respect to the items tapping restricted interests and repetitive behaviors. Items 80. "Strange behavior;" 63. "Repeatedly rocks head or body;" 67. "Seems unresponsive to affection;" and 98. "Withdrawn, doesn't get involved with others" had low base rates in these population samples across societies and types of informants, suggesting that they may be particularly discriminating for identifying autism spectrum disorder in young children. Cross-informant agreement was stronger for the items tapping social communication and interaction problems than restricted interests and repetitive behaviors. The findings support the feasibility of international use of the scale for autism spectrum disorder screening in population samples.

We analyzed CBCL/1½-5 Pervasive Developmental Problems (DSM-PDP) scores in 3- to 5-year-olds from the Study to Explore Early Development (SEED), a multi-site case control study, with the objective to discriminate children with ASD (N = 656) from children with Developmental Delay (DD) (N = 646), children with Developmental Delay (DD) plus ASD features (DD-AF) (N = 284), and population controls (POP) (N = 827). ASD diagnosis was confirmed with the ADOS and ADI-R. With a cut-point of T = 65, sensitivity was 80% for ASD, with specificity varying across groups: POP (0.93), DD-noAF (0.85), and DD-AF (0.50). One-way ANOVA yielded a large group effect (?[superscript 2] = 0.50). Our results support the CBCL/1½-5's as a time-efficient ASD screener for identifying preschoolers needing further evaluation.

Children with language disorders have particular difficulty with verbs, but when this difficulty emerges is unknown. We examined syntactic (transitive, intransitive, ditransitive) and semantic (manner, result) features of two-year-olds' verb vocabularies, contrasting late talkers and typically developing children to look for early differences in verb vocabulary. We conducted a retrospective analysis of parent-reported expressive vocabulary from the Language Development Survey (N = 564, N(LT) = 62) (Rescorla, 1989). Verbs were coded for the presence or absence of each syntactic and semantic feature. Binomial mixed-effects regressions revealed the effect of feature on children's knowledge and whether feature interacted with group classification. Our results revealed mostly similarities between late talkers and typically developing children. All children's vocabularies showed a bias against verbs that occur in ditransitive frames. One feature showed a difference between groups: late talkers showed a bias against manner verbs that typically developing children did not.

Although the Child Behavior Checklist 1½-5's 12-item "Diagnostic and Statistical Manual of Mental Disorders"-Autism Spectrum Problems Scale (formerly called Pervasive Developmental Problems scale) has been used in several studies as an autism spectrum disorder screener, the base rate and stability of its items and its measurement model have not been previously studied. We therefore examined the structure, longitudinal invariance, and stability of the Child Behavior Checklist 1½-5's "Diagnostic and Statistical Manual of Mental Disorders"-Autism Spectrum Problems Scale in the diverse Generation R (Rotterdam) sample based on mothers' ratings at 18 months (n = 4695), 3 years (n = 4571), and 5 years (n = 5752). Five items that seemed especially characteristic of autism spectrum disorder had low base rates at all three ages. The rank order of base rates for the 12 items was highly correlated over time (Qs ? 0.86), but the longitudinal stability of individual items was modest (phi coefficients = 0.15-0.34). Confirmatory factor analyses indicated that the autism spectrum disorder scale model manifested configural, metric, and scalar longitudinal invariance over the time period from 18 months to 5 years, with large factor loadings. Correlations over time for observed autism spectrum disorder scale scores (0.25-0.50) were generally lower than the correlations across time of the latent factors (0.45-0.68). Results indicated significant associations of the autism spectrum disorder scale with later autism spectrum disorder diagnoses.

The screening power of the CBCL/1½-5's Withdrawn and "Diagnostic and Statistical Manual of Mental Disorders"-Pervasive Developmental Problems (DSM-PDP) scales to identify children diagnosed with autism spectrum disorder at 24 months was tested in a longitudinal, familial high-risk study. Participants were 56 children at high risk for autism spectrum disorder due to an affected older sibling (high-risk group) and 26 low-risk children with a typically developing older sibling (low-risk group). At 24 months, 13 of the 56 high-risk children were diagnosed with autism spectrum disorder, whereas the other 43 were not. The high-risk children diagnosed with autism spectrum disorder group had significantly higher scores on the CBCL/1½-5's "Diagnostic and Statistical Manual of Mental Disorders"-Pervasive Developmental Problems and Withdrawn scales than children in the low-risk and high-risk children not diagnosed with autism spectrum disorder groups ([eta][subscript p][superscript 2]>0.50). Receiver operating characteristic analyses yielded very high area under the curve values (0.91 and 0.89), and a cut point of T [greater than or equal to] 60 yielded sensitivity of 77% and specificity of 97% to 99% between the high-risk children diagnosed with autism spectrum disorder and the combination of low-risk and high-risk children not diagnosed with autism spectrum disorder. Consistent with several previous studies, the CBCL/1½-5's "Diagnostic and Statistical Manual of Mental Disorders"-Pervasive Developmental Problems scale and the Withdrawn syndrome differentiated well between children diagnosed with autism spectrum disorder and those not diagnosed.

Purpose: The objective of this study was to compare vocabulary size and composition in 2-year-olds learning Polish or English as measured by the Language Development Survey (LDS; Rescorla, 1989). Method: Participants were 199 Polish toddlers (M = 24.14 months, SD = 0.35) and 422 U.S. toddlers (M = 24.69 months, SD = 0.78). Results: Test-retest reliability was 0.92, internal consistency was 0.99, and concurrent validity was 0.55. Girls had higher vocabulary scores than boys. Mean LDS score was significantly lower in Polish than in English, and fewer Polish children had LDS scores >200 words. Also, more words were reported for <25% of the children, and fewer words were reported for =75% of the children, in Polish than in English. The cross-linguistic correlation for word frequencies was 0.44. Noun dominance was comparable in the two languages, and 55 cross-linguistic word matches were found among the top 100 words. Although more Polish than U.S. children had <50 words (18.1% vs. 8.3%), children with <50 words and those with =50 words were generally acquiring the same words. Conclusions: Vocabulary acquisition appeared to be slower in Polish than in English, probably because of the complexity of the language. However, the languages were very similar with respect to vocabulary composition findings.

Purpose: Our objective was to replicate previous cross­linguistic findings by comparing Portuguese and U.S. children with respect to (a) effects of language, gender, and age on vocabulary size; (b) lexical composition; and (c) late talking. Method: We used the Language Development Survey (LDS; Rescorla, 1989) with children (18-35 months) learning European Portuguese (n = 181) and English (n = 206). Results: In both languages, girls had higher vocabulary scores than boys and vocabulary scores increased with age. Portuguese LDS scores were significantly lower than English scores, but the effect size was small. Cross­linguistic concordance of percentage use scores yielded a Q correlation of 0.50, with 64 of the "top 100" words being exact matches. Cross­linguistic concordance was highest for the youngest age group. In both languages, vocabulary composition in late talkers (children = 24 months with < 50 words) was highly correlated with composition in vocabulary size­matched younger children. Conclusions: Results replicated previous Greek, Korean, and Italian LDS studies. The early lexicons of typical talkers and late talkers contained many of the same words, indicating considerable universality and suggesting good targets for clinical intervention.

The present study examined the relation between language and social ability in a sample of 268 preschoolers aged 18-35 months. Expressive language was assessed with the Italian adaptation of the Language Development Survey (LDS), and Social Competence was assessed with the Questionnaire on Peer Interactions in the Kindergarten (QPI). Results showed that language measures (LDS Vocabulary, LDS MLU and the opportunity scores of the LDS category of People Words) predicted social competence (Total QPI score and the standardised scores of the "Popularity", "Prosociality", "Aggressiveness", "Adult Dependence", and "Isolation" factors), above and beyond the proportion of variance explained by age. In addition, children with delayed language development (who were older than 24 months and produced fewer than 50 words) exhibited lower social abilities, compared to age-matched children. These findings support the conclusion that language skills play a critical role for social adjustment.

To test the Child Behavior Checklist's (CBCL/1½-5) ability to screen for autism spectrum disorders (ASD), we studied Korean preschoolers: 46 with ASD, 111 with developmental delay (DD), 71 with other psychiatric disorders (OPD), and 228 non-referred (NR). The ASD group scored significantly higher than the other groups on the Withdrawn and DSM-Pervasive Developmental Problems (DSM-PDP) scales as well as attaining higher scores (p < 0.001) on seven items reflecting ASD. With a T = 65 cutpoint on the DSM-PDP scale, sensitivity was 80% for identifying ASD relative to the other three groups, but specificity varied across groups: NR = 87%, OPD = 55%, DD = 60%, replicating in a non-Western sample results from previous studies. Results suggested that the CBCL/1½-5 performs best in Level 1 screening, namely differentiating children with ASD from children in the general population.

Purpose: This study reports age 5 morphology and syntax skills in late talkers identified at age 2 (n = 34) and typically developing comparison children (n = 20). Results: The late talkers manifested significant morphological delays at ages 3 and 4 relative to comparison peers. Based on the 14 morphemes analyzed at age 5, the only significant group difference was on the third person regular "-s" inflection. This was also the only significant difference when we compared late talkers with continuing delay, late bloomers (who scored within 1 standard deviation of the comparison group in mean length of utterance), and typically developing peers. The late talker and comparison children differed greatly in mean total scores on the Index of Productive Syntax (Scarborough, 1990), a measure of syntactic complexity. The group with continuing delay scored significantly lower on the IPSyn than the late bloomer and typically developing groups, which did not differ from each other. Conclusions: Findings are consistent with the higher order language group differences found through adolescence in these late talkers relative to comparison peers with similar socioeconomic status and similar nonverbal abilities, supporting the notion that late talkers have an ongoing weakness in language endowment that manifests differently over the course of development.

Purpose: The Language Development Survey (LDS; Rescorla, 1989) was used to compare Italian and English lexical development. The authors addressed the issue of universal versus language-specific aspects of lexical development by testing language, age, and gender effects on vocabulary scores and by comparing vocabulary composition across languages. They addressed the issue of delay versus deviance by comparing vocabulary composition in late talkers and younger vocabulary-size-matched children. Method: Participants were 398 Italian and 206 U.S. children ages 18-35 months. Results: Vocabulary size did not differ significantly by language, and age and gender effects on vocabulary size were not moderated by language. The Italian-English Q correlation for percentage word use scores was 0.55, lower than the within-language concordance of 0.90 and above. Cross-linguistic concordance declined as age and vocabulary size increased. Many cross-linguistic word matches (63 words) were found among the top 100 words. Italian late talkers were similar to younger vocabulary-size-matched Italian children in vocabulary composition, consistent with findings for English, Greek, and Korean. Conclusions: In both languages, the early lexicons of late talkers and typical talkers contained many of the same words, indicating considerable universality in young children's lexical development. These common words are therefore good targets for clinical intervention.

This study evaluated the ability of the Child Behavior Checklist and the Teacher's Report Form to identify children with autism spectrum disorders (ASD), using a sample of children with ASD (n = 458), referred children without ASD (n = 1109) and children from the general population (n = 999). A ten items ASD scale was constructed using half of the sample and the ability of this scale to discriminate between children with ASD and the other children was tested for the CBCL and the TRF separately and together in the other half of the sample. Using a cut-off score of 8 the combined CBCL/TRF ASD scale demonstrated high predictive values (NPV 95%, PPV 73%) in identifying children with ASD and children in the general population sample. This might be an acceptable percentage of false positives in general screening, considering the chance that these children might have other behavioural, emotional, and developmental problems which also need psychiatric evaluation. In the referred population, using a cut-off of 13, PPV was 49% and NPV was 85%. The high NPV indicates that in a referred population the scale is especially good at identifying children who do not need evaluation with a more ASD-specific instrument.

Purpose: The authors tested associations between (a) parent-reported temporary vs. persistent vocabulary delay and (b) parent-reported behavioral/emotional problems in a sample of 5,497 young Dutch children participating in a prospective population-based study. Method: Mothers completed the MacArthur Communicative Development Inventory--Netherlands (Zink & Lejaegere, 2003) at age 18 months and the Language Development Survey (Rescorla, 1989) at age 30 months, with expressive vocabulary delay defined as scores in the lowest 15th age and gender-specific percentiles. The Child Behavior Checklist (Achenbach & Rescorla, 2000) was completed by mothers when their children were age 18 months and by both parents when their children were age 36 months, from which Internalizing Problems and Externalizing Problems scores were analyzed. Results: All analyses were adjusted for covariates. Expressive vocabulary delay at age 18 months was weakly related to Internalizing Problems scores at age 18 months as well as mother-reported Externalizing and Internalizing Problems scores at age 36 months (the latter for boys only). Expressive vocabulary delay at age 30 months was weakly associated with mother-reported Externalizing and Internalizing Problems scores (the latter for boys only) and father-reported Internalizing Problems scores. Persistent expressive vocabulary delay predicted the highest risk of mother-reported internalizing and externalizing problems at age 36 months. Conclusion: This population-based study showed modest associations between vocabulary delay and behavioral/emotional problems detectable from 18 months onward. (Contains 4 tables, 1 figure, and 2 footnotes.)

Purpose: In this study, the authors aimed to compare vocabulary size, lexical composition, and late talking in large samples of Korean and U.S. children ages 18-35 months. Method: Data for 2,191 Korean children (211 children recruited "offline" through preschools, and 1,980 recruited "online" via the Internet) and 274 U.S. children were obtained using the Language Development Survey (LDS). Results: Mean vocabulary size was slightly larger in the offline than the online group, but the groups were acquiring almost identical words. Mean vocabulary size did not differ by country; girls and older children had larger vocabularies in both countries. The Korean-U.S. Q correlations for percentage use of LDS words (0.53 and 0.56) indicated considerable concordance across countries in lexical composition. Noun dominance was as large in Korean lexicons as in U.S. lexicons. About half of the most commonly reported words for the Korean and U.S. children were identical. Lexicons of late talkers resembled those of typically developing younger children in the same sample. Conclusions: Despite linguistic and discourse differences between Korean and English, LDS findings indicated considerable cross-linguistic similarity with respect to vocabulary size, lexical composition, and late talking. (Contains 1 figure and 2 tables.)

We used population sample data from 25 societies to answer the following questions: (a) How consistently across societies do adolescents report more problems than their parents report about them? (b) Do levels of parent-adolescent agreement vary among societies for different kinds of problems? (c) How well do parents and adolescents in different societies agree on problem item ratings? (d) How much do parent-adolescent dyads within each society vary in agreement on item ratings? (e) How well do parent-adolescent dyads within each society agree on the adolescent's deviance status? We used five methods to test cross-informant agreement for ratings obtained from 27,861 adolescents ages 11 to 18 and their parents. Youth Self-Report (YSR) mean scores were significantly higher than Child Behavior Checklist (CBCL) mean scores for all problem scales in almost all societies, but the magnitude of the YSR-CBCL discrepancy varied across societies. Cross-informant correlations for problem scale scores varied more across societies than across types of problems. Across societies, parents and adolescents tended to rate the same items as low, medium, or high, but within-dyad parent-adolescent item agreement varied widely in every society. In all societies, both parental noncorroboration of self-reported deviance and adolescent noncorroboration of parent-reported deviance were common. Results indicated many multicultural consistencies but also some important differences in parent-adolescent cross-informant agreement. Our findings provide valuable normative baselines against which to compare multicultural findings for clinical samples. (Contains 5 tables and 1 figure.)

For sixty-seven children with ASD (age 1;6 to 5;11), mean Total Vocabulary score on the Language Development Survey (LDS) was 65.3 words; twenty-two children had no reported words; and twenty-one children had 1-49 words. When matched for vocabulary size, children with ASD and children in the LDS normative sample did not differ in semantic category or word-class scores. "Q" correlations were large when percentage use scores for the ASD sample were compared with those for samples of typically developing children as well as children with vocabularies less than 50 words. The 57 words with the highest percentage use scores for the ASD children were primarily nouns, represented a variety of semantic categories, and overlapped substantially with the words having highest percentage use scores in samples of typically developing children as well as children with lexicons of less than 50 words. Results indicated that the children with ASD were acquiring essentially the same words as typically developing children, suggesting delayed but not deviant lexical composition.

This study tested societal effects on caregiver/teacher ratings of behavioral/emotional problems for 10,521 preschoolers from 15 societies. Many societies had problem scale scores within a relatively narrow range, despite differences in language, culture, and other characteristics. The small age and gender effects were quite similar across societies. The rank orders of mean item ratings were similar across diverse societies. For 7,380 children from 13 societies, ratings were also obtained from a parent. In all 13 societies, mean Total Problems scores derived from parent ratings were significantly higher than mean Total Problems scores derived from caregiver/teacher ratings, although the size of the difference varied somewhat across societies. Mean cross-informant agreement for problem scale scores varied across societies. Societies were very similar with respect to which problem items, on average, received high versus low ratings from parents and caregivers/teachers. Within every society, cross-informant agreement for item ratings varied widely across children. In most respects, results were quite similar across 15 very diverse societies. (Contains 5 tables and 1 figure.)

This study examined the criterion validity of the Child Behavior Checklist (CBCL) and Teacher's Report Form (TRF) problem scales and items in demographically-matched Singapore samples of referred and non-referred children (840 in each sample for the CBCL and 447 in each sample for the TRF). Internal consistency estimates for both the CBCL and TRF scales were good. Almost all CBCL and TRF problem scales and items significantly discriminated between referred and non-referred children, with referred children scoring higher, as expected. The largest referral status effects were on attention problems scales and their associated items, with the TRF having larger effects than the CBCL. Effect sizes for demographic variables such as age, gender, ethnicity and SES were much smaller than effect sizes for referral status, across both the CBCL and TRF forms and at both the scale and item levels. These findings suggest that teachers can be effective partners in identifying children who need mental health services and those who do not.

The present study examined agreement between scores obtained from self-reports of behavioral and emotional problems obtained from 513 Algerian adolescents on the Youth Self-Report (YSR) with scores obtained from reports provided by their parents on the Child Behavior Checklist (CBCL). The correlations between self- and parent-report were larger than those observed in many other cultures (e.g., intraclass correlation coefficient = 0.60 and Pearson r = 0.65 for Total Problems). On the whole, cross-informant agreement did not vary significantly as a function of problem type, identity of the parental informant, gender and age of the adolescent. Similar to all studied cultures, adolescents on average reported more problems than their parents reported about them, but the discrepancies were smaller than in all previous societies. Mean YSR/CBCL score discrepancies indicated higher YSR scores for several scales, but variability across dyads was large, and many dyads showed the opposite pattern. (Contains 3 tables.)

We tested the ability of the 2001 CBCL syndromes to discriminate among 86 children with Autism Spectrum Disorder (ASD), 117 children with Attention Deficit Hyperactivity Disorder-Inattentive type, 426 children with Attention Deficit Hyperactivity Disorder-Hyperactive-Impulsive or Combined type, 200 clinically referred children who did not receive a diagnosis, and 436 typically-developing children in a community sample. The Withdrawn/Depressed, Social Problems, and Thought Problems syndromes significantly discriminated the ASD group from the four other groups. An ASD scale, constructed from nine CBCL items, demonstrated moderate to high sensitivity (68 to 78%) and specificity (73 to 92%). Consistent with previous research, findings from this study provide strong support for the CBCL as a screening tool for ASD.

This study investigated vocabulary size and vocabulary composition in Greek children aged 1 ; 6 to 2 ; 11 using a Greek adaptation of Rescorla's Language Development Survey (LDS; Rescorla, 1989). Participants were 273 toddlers coming from monolingual Greek-speaking families. Greek LDS data were compared with US LDS data obtained from the instrument's normative sample (Achenbach & Rescorla, 2000). Vocabulary size increased markedly with age, but Greek toddlers appeared to get off to a slower start in early word learning than US children. The correlation between percentage word use scores in Greek and US samples was moderate in size, indicating considerable overlap but some differences. Common nouns were the largest category among the fifty most frequent words in both samples. Numbers of adjectives and verbs were comparable across languages, but people and closed-class words were more numerous in the Greek sample. Finally, Greek late talkers showed similar patterns of vocabulary composition to those observed in typically developing Greek children.

Comparisons of Child Behavior Checklist (CBCL) scores from 31 societies (Rescorla et al. "Journal of Emotional and Behavioral Disorders" 15:13-142 2007) supported the instrument's multicultural robustness, but none of these societies was in South America. The present study tested the multicultural robustness of the 2001 CBCL using data from a national epidemiological survey in Uruguay. Participants were 1,374 6- to 11-year-olds recruited through 65 schools nationwide; 1,098 (80%) had received no mental health or special education services in the past year ("non-referred" group), whereas 276 ("referred" group) had been referred for mental health services, had repeated greater than or equal to 2 grades, or had significant developmental disabilities. Mean item ratings, factor structure, and scale internal consistencies were very similar to findings reported by Rescorla et al. ("Journal of Emotional and Behavioral Disorders" 15:13-142 2007) and Ivanova et al. ("Journal of Clinical Child and Adolescent Psychology" 36: 405-417 2007). Children from low SES school environments obtained higher problem scores, especially in the referred group. Gender, age, and referral status effects paralleled those in the U.S. Non-referred children obtained somewhat higher mean problem scores in Uruguay than in the U.S., but mean score differences between non-referred and referred children were smaller in Uruguay than the U.S. Findings supporting the CBCL's multicultural robustness in a South American country extend the generalizability of findings reported by Rescorla et al. ("Journal of Emotional and Behavioral Disorders" 15:13-142 2007) for 31 societies.

Purpose: The authors investigated continuity and discontinuity of vocabulary skills in a population-based cohort in the Netherlands. Method: Mothers of 3,759 children completed the Dutch version of the MacArthur Short Form Vocabulary Checklist (Zink & Lejaegere, 2003) at 18 months and a Dutch translation of the Language Development Survey (Rescorla, 1989) at 30 months. At both ages, expressive vocabulary delay was defined as vocabulary scores less than 10th age- and gender-specific percentile. Results: Of the children, 85.2% had normal vocabulary development at both ages, 6.2% were "late bloomers," 6.0% had late onset expressive vocabulary delay, and 2.6% had persistent expressive vocabulary delay. Word production and comprehension at 18 months explained 11.5% of the variance in 30-month vocabulary scores, with low birth weight, child age, gender and ethnicity, maternal age and education, and parenting stress explaining an additional 6.2%. Multinomial logistic regression was used to identify biological, demographic, and psychological factors associated with each of the vocabulary delay outcome groups relative to the typically developing group. Conclusions: Although multiple perinatal, demographic, and maternal psychosocial factors significantly predicted vocabulary skills at 30 months, positive predictive value and sensitivity were low. Future studies should address to what extent additional factors, such as brain maturation and genetic influences, can improve the prediction and understanding of continuity and discontinuity of language delay.