predictors of persistence in a longitudinal preventive intervention program for young disruptive...

P1: GVM/GYQ/LCR/GFQ/GIR P2: GCP

Prevention Science [PREV] PP247-344676 August 10, 2001 7:38 Style file version Nov. 04, 2000

Prevention Science, Vol. 2, No. 3, September 2001 ( C© 2001)

Predictors of Persistence in a Longitudinal PreventiveIntervention Program for Young Disruptive Boys

Pierre Charlebois,1,2 Frank Vitaro,1 Sylvie Normandeau,1 and Normand Rondeau1

Several investigators have underlined the importance of long-term prevention programs inorder to expect positive results for at-risk children. One essential prerequisite to addressingthis issue is the retention of participants in such programs. The present study aims at exam-ining the contribution of mother–child interactions, mother’s social isolation, improvement inthe mother–child relationship, and improvement in the child’s behavior to the prediction ofpersistence. Participants (n = 59 disruptive boys) were recruited for a 3-year multicomponentpreventive intervention program. Results indicated an improvement of the boys’ behavior(reduction of inattention/hyperactivity and reduction of fighting) during the first year of theprogram, and showed that mother–child positive interactions before the beginning of theprogram were the best predictors of persistence. Implications of these results for long-termpreventive programs are discussed.

KEY WORDS: persistence; disruptive boys; multicomponent intervention; longitudinal; preventive in-tervention.

LIST OF ABBREVIATIONS

SOT Short-term outpatient treatmentETLP Early-age-targeted-longitudinal-preven-

tive interventionPBQ Preschool Behavior QuestionnairePSI Parental Strees IndexWISC-R Weschler Children Intelligence

Scale—RevisedWAIS-R Weschler Adult Intelligence Scale—Revi-

sed

Research has shown that time-limited preven-tive interventions for at-risk children and adolescentshave produced limited short-term outcomes. Severalinvestigators in the field have recommended a sig-nificant increase in the duration of interventions in

1Ecole de psychoeducation, University of Montreal, Montreal,Quebec, Canada.

2Correspondence should be directed to Pierre Charlebois, Ecole depsychoeducation, Faculte des arts et des sciences, C.P. 6128, suc-cersale centre-ville, Montreal, Quebec H3C 3J7, Canada; e-mail:[email protected].

order to promote maintenance of behavior changesover time (Abikoff, 1985; Kazdin, 1996a; Lochman,1985; Mash, 1999; Schneider, 1992; Tremblay et al.,1999). Yokishawa (1994) underlined the importanceof designing preventive intervention programs with aduration of at least 2 years in order to expect positiveresults.

One essential prerequisite to addressing this is-sue is the retention of participants in such preventionprograms. Attrition or loss of cases has always repre-sented a major obstacle for prevention research. Pro-grams with a longer duration are the most plaguedbecause attrition increases with the span of timeneeded to complete the intervention. Loss of cases isa threat to all facets of experimental validity becauseit alters the random composition of groups, reducesstatistical power, and limits generalizability of theconclusions (Kazdin, 1996b). Short-term outpatienttreatment (SOT) studies on attrition have shown that50–75% of youths referred for treatment terminateprematurely (Armbruster & Kazdin, 1994; Kazdinet al., 1993; Kazdin & Mazurick, 1994; Wierzbicki& Pekarik, 1993). The figures for early-age-targeted-longitudinal-preventive interventions (ETLP) are

1331389-4986/01/0900-0133$19.50/1 C© 2001 Society for Prevention Research



134 Charlebois, Vitaro, Normandeau, and Rondeau

very similar. Although the children’s participationwas high (95%) in some programs when activitieswere integrated into the academic curriculum, par-ticipation in other program components (e.g., parenttraining) generally decreased with time. Moreover,a dramatic drop in participation generally occurredafter the first year of the programs. In this respect,Braswell et al. (1997) and Cohen and Rice (1995) re-ported an attrition of over 72% of the parents at thebeginning of the second year of their multicompo-nent program. The authors of the present study alsodeveloped a multicomponent program for disruptiveboys (including boys’ social and self-regulation skillstraining, parent skills training, and teachers’ class-room strategies), which extended over a 3-year pe-riod (Charlebois, 2000). Attrition also occurred in thismulticomponent program after the first year (56%),but families who continued after the first year (44%)completed the 3-year program. The identification offactors that predict attrition and the development ofstrategies to minimize their effects are thus essentialin order to increase the effectiveness of preventiveinterventions.

Investigations to document factors that influ-ence attrition have been conducted mainly in SOT.Some studies have focused on child, parent, or familycharacteristics, whereas others have focused on prob-lem improvement over time and participant satisfac-tion with treatment. The first set of studies identifiedseveral sociofamilial factors (e.g., race, socioeco-nomic disadvantage, adverse child-rearing prac-tices), parental characteristics (e.g., maternal depres-sion, stress, life events, history of antisocial behavior,social isolation), and child functioning variables (e.g.,severe and chronic antisocial behavior, lower IQ, con-flict in peer relations), which predicted premature de-parture from treatment (Armbruster & Kazdin, 1994;Armbruster & Schwab-Stone, 1994; Kazdin et al.,1993; Kazdin et al., 1995; Kazdin & Mazurick, 1994).Other studies showed that dissatisfaction with im-provement over the course of treatment could alsobe an important reason for dropping out of treat-ment. Pekarik (1992) showed that participants whoimproved over the course of treatment had superioroutcomes and expressed more satisfaction with thetreatment program than did dropouts. Similar findingsby Kazdin and Wassell (1998) underlined the impor-tance of ongoing assessment of progress to advanceknowledge on the factors that predict premature ter-mination of treatment.

Notwithstanding the important contribution ofprevious studies to the prediction of attrition in

SOT, the findings reported earlier could possiblybe less relevant to the prediction of attrition inETLP. Factors predicting attrition in ETLP couldbe different for several reasons. First, the recruit-ment strategy in preventive intervention is somewhatdifferent from the referral system used in short-term outpatient treatments. In SOT, participants areeither self-referred (i.e., parents seek relief from adifficult situation created by the child’s behaviorproblems) or referred to an outpatient treatmentby teachers, school professionals, or social workers(Mash & Terdal, 1997). In ETLP, researchers ap-proach participants who are typically not activelyseeking help.

Second, when children are referred or self-referred for treatment in SOT, the behavior problemhas usually developed over time and caregivers’ dis-tress over childcare and child management is likely tobe very high. In ETLP, participants are approachedwhen children are still at an early age and parents areusually less aware that their child presents or is at riskfor behavior problems. Kazdin (1996b) showed thataggravation and duration of child behavior problemsare important determinants of dropping out of short-term outpatient treatments. These differences couldhave important differential effects on the motivationto participate and on the compliance to the treatmentprogram (Mash, 1999).

Third, sufficient variance in the characteristics ofparticipants involved in SOT studies (i.e., age varyingfrom 6 to 12, gender, socioeconomic status, race, IQ,differences in families’ antisocial background) madeit possible to examine the role of these characteris-tics in the prediction of attrition. A similar analysiswould also be possible in ETLP if some personal dis-positions or families’ antisocial background variableswere assessed but not used as selection criteria. Par-ticipants’ selection characteristics, however are lesslikely to discriminate persisters from nonpersisterswhen a restricted range is imposed on these vari-ables by the selection procedure (see Tremblay et al.,1999 for a review). This inevitably forces the searchfor other reliable predictors of persistence in ETLP.Considering the nature of ETLP (i.e., the need to ap-proach participants not seeking out help, the necessityto describe the program content in such a way as toentice participants), participants’ perception of pro-gram demands in relation with their perceived per-sonal competence could be important determinantsof enrollment and persistence in the program (Kazdin& Wassell, 1999). For example, considering that mostETLP programs propose group parent training, the



Predictors of Persistence 135

perception of one’s competence in a group situationcould be a determining factor of adhesion to a pro-gram. Moreover a mother’s perception of the qualityof her relationship with her child and of her compe-tence in raising her child could also be a determin-ing factor in her enrollment and persistence in theprogram (Forehand & McMahon, 1981; Patterson &Forgatch, 1995).

Thus, considering that the parent component ofthe present program included group sessions on par-enting skills and training sessions on the managementof parent–child conflicts, the mother’s perception ofher social competence (i.e., satisfaction with her so-cial contacts), and the quality of mother–child inter-actions before the beginning of treatment were con-sidered to be important factors for persistence in theprogram. Improvements in the mother–child relation-ship and in the child’s social skills during the first yearof the program were also considered to be importantincentives in the participants’ persistence in the 3-yearprogram.

In the absence of a theoretical model to explainpersistence in ETLP programs, the present study aimsto examine the unique and cumulative contributionof (1) mother–son interactions before the beginningof the program; (2) mothers’ social contacts beforethe beginning of the program; (3) and improvementin the mother–child relationship and in the children’sbehaviors during the first year of the program, to theprediction of persistence in a 3-year multicomponentETLP program.

METHOD

Participants

Fifty-nine disruptive boys, their parents and theirteachers participated voluntarily in a 3-year multi-component program designed to prevent school un-derachievement. Participants were selected throughthe use of the following multiple screening procedure.First, boys (n = 1100) from kindergarten classes intwo small towns in Quebec, Canada, were assessed atthe end of the school year by their teachers using thePreschool Behavior Questionnaire (PBQ, Behar &Stringfield, 1974). Second, a letter of participation anda series of questionnaires were mailed to the parentsof the 330 boys who scored above the population 70thpercentile (as established with a provincial sample) onthe PBQ Inattention–Hyperactivity and Aggressive-ness subscales. A $10 reward was offered for returned

questionnaires. Third, out of the 330 boys, those wereselected who were also described by their mothers asinattentive–hyperactive and aggressive on the PBQ(above the population 70th percentile), whose moth-ers had a score above the 75th percentile (i.e., thresh-old for referral and professional services or both) onthe mother’s total stress scale of the Parental StressIndex (PSI, Abidin, 1986) and who were of low so-cioeconomic status (Canadian census norms, 1991).Results for the recruitment were as follows: n = 181who accepted to participate but did not meet selec-tion criteria were rejected; n = 21 who met all thecriteria but were moving to another region in Julywere excluded; n = 8 refused to participate. The finalpool of subjects was thus composed of 120 Caucasian,French-speaking Canadian boys. The current paperreports only on the experimental boys (n = 59) whoparticipated in the skills training program. One casehad too many missing data to be included in theanalyses.

Assessment of the participants and their moth-ers was conducted during the summer (June–August) between kindergarten and the first grade.The Weschler Adult Intelligence Scale—Revised(WAIS-R, Weschler, 1991b) and the Minnesota Mul-tiphasic Personality Inventory (MMPI, Dahlstromet al., 1975) were used to assess mothers’ IQ andpersonality. The boys’ IQ was assessed usingthe Weschler Children Intelligence Scale—Revised(WISC-R, Weschler, 1991a). The boys and theirmothers also participated in a computerized learn-ing task aimed at assessing mother–child interaction(Charlebois et al., 1995). Their agreement to fill outquestionnaires and to participate in this 2.5 hr labo-ratory session during the summer was considered agood indicator of the mothers’ motivation to engagein the voluntary prevention program. The screeningprocedure selected a homogenous group, controllingfor factors usually considered in previous ETLP stud-ies (i.e., gender, age, socioeconomic status, severity ofproblems, IQ, physical health, mother’s psychopathol-ogy, parent stress, mother’s education). Means andstandard deviations are presented in Tables 1 and 2.Correlations between baseline and T2 assessmentsare also presented as indices of stability. As canbe seen from these tables, boys’ and mothers’ char-acteristics that were not targeted by the interven-tion were stable over time (e.g., boys’ and mothers’physical health, mothers’ education, family socioeco-nomic status). Assessments of boys’ and mothers’ IQand of mothers’ psychopathology were not repeatedat T2.




Table 1. Means and Standard Deviations of Boys’ Characteristicsat Baseline and Stability Indices (T1 vs. T2). (n = 120)

Domain and measure M SD Pearson r

PBQ (mother)Aggressiveness 8.7 3.4 .64∗∗

Anxiety 4.6 2.3 .35∗∗

Inattention–hyperactivity 7.4 3.0 .44∗∗

Prosociality 10.6 4.0 .57∗∗

PBQ (teacher)Aggressiveness 6.6 5.4 .56∗∗

Anxiety 3.5 2.7 .95∗∗

Inattention–hyperactivity 8.6 2.7 .30∗∗

Prosociality 4.0 4.1 .83∗∗

IQ (WISC-R)Total 96.2 13.9 n.a.

Physical healtha 0.02 0.04 .90∗∗

Note. PBQ = Preschool Behavior Questionnaire; WISC-R =Weschler Children Intelligence Scale—Revised; n.a. = not avail-able because not assessed at T2.aHospitalization, chronic illness, medical consultation.∗∗ p < .01.

Assessment of Boys’ Initial Characteristics

Boys’ Behaviors

Teachers and mothers filled out the PreschoolBehavior Questionnaire (PBQ, Behar & Stringfield,1974) at pretest and after the first year of interven-tion. The PBQ includes three scales: inattention–hyperactivity (6 items: has poor concentration, hasdifficulty sustaining attention on tasks, gives up, staresinto space, has difficulty remaining seated, fidgetsor squirms in seat); aggressiveness (9 items: fights,bullies, hits, bites, kicks, disobeys, destroys objects,does not share, lies, blames others, is moody), andanxiety (11 items: is worried, is withdrawn, is sad,sucks thumb, bites nails, is afraid, wets bed, stutters,cries frequently). A fourth scale was added to thequestionnaire to assess prosocial behaviors (7 items:tries to interrupt peer conflicts, invites others to play,helps someone who is hurt, helps to pick up ob-jects, praises others, comforts others, offers help), be-cause it was believed that prosociality could attenuatethe severity of antisocial behaviors (Weir & Duveen,1986). Each item could be rated either 0 (does not ap-ply), 1 (sometimes), or 2 (often). The PBQ has provento be reliable in the assessment of behavior problemsin children (Behar & Stringfield, 1974; Martin, 1988).It has been widely used both in North America andin Europe and has shown stability in factor structureacross genders, ages, socioeconomic levels, and cul-tures (Tremblay et al., 1987).

IQ Assessment

A trained professional assessed each boy’s IQaccording to the procedures described in the manualfor the Weschler Intelligence Scale for Children—Revised (WISC-R, Weschler, 1991a). This instru-ment has been widely used to assess the IQ ofdisruptive children and children with learning dis-abilities (Prifitera & Dersh, 1993). The arithmetic,blocks, and vocabulary scales were used in the presentstudy to estimate the boys’ IQ. The boys’ mean forthe three scales was in the normal range (M = 10,SD = 3).

Assessment of Boys’ Physical Health

Mothers completed a general information sheetto describe the child’s number of hospitalizations, ill-nesses, chronic illnesses, number of consultations withmedical specialists, consultations with a dentist, andprescriptions of medication since the child’s birth.

Table 2. Means and Standard Deviations for Mothers’ Character-istics, Family Socioeconomic Status, Observations of Mother–Son

Interactions and Stability Indices (T2 − T1). (n = 120)

Domain and measure M SD Pearson r

IQ (WAIS-R)Blocks 9.2 3.1 n.a.Vocabulary 7.3 2.2 n.a.Education 10.8 2.0 .81∗∗

Parent stress (PSI)Total 244.4 47.6 .74∗∗

Psychopathology (MMPI)Hypochondria 4.3 1.8 n.a.Depression 5.6 1.6 n.a.Hysteria 6.1 2.8 n.a.Psychopathy 10.2 2.3 n.a.Paranoia 5.2 2.9 n.a.Psychostenia 3.8 1.9 n.a.Schizophrenia 2.5 1.7 n.a.Hypomania 4.8 2.3 n.a.Social contactsa 1.1 4.1 .63∗∗

Physical healthb 12.6 3.4 .67∗∗

Observations (mother–son)Positive (mother) 8.1 6.7 .11Aversive (mother) 0.8 2.1 .01Positive (son) 5.1 4.8 .11Negative (son) 0.5 1.4 .05Income (×$10,000) 3.4 1.93 .78∗∗

Note. WAIS-R = Weschler Adult Intelligence Scale—Revised;PSI = Parental Stress Index; MMPI=Minnesota Multiphasic Per-sonality Inventory; n.a.= not available because not assessed at T2.aNumber of social contacts per week/perception of isolation.bHospitalization + chronic illness + medical consultation.∗∗ p < .01.




Frequencies for each item were computed to create ahealth index (e.g., 1 consultation with a medical spe-cialist +1 consultation with a dentist = 2). Boys werein good physical health.

Assessment of Mothers’ Initial Characteristics

The mother measures were collected when theboys were 6 years old. Assessment of the parents’characteristics was limited to mothers (all were bio-logical mothers) because mothers remain the primarycaretakers of the child and because many fathers wereno longer living with the child. The proportion of sin-gle mothers was 50%.

Mothers’ IQ

A trained professional assessed each mother’s IQaccording to the procedures described in the manualfor the Weschler Adult Intelligence Scale—Revised(WAIS-R, Weschler, 1991b). This instrument hasbeen widely used to assess the IQ of adults (Weschler,1991b). The blocks and vocabulary scales were used toestimate mothers’ IQ in the present study. As can beseen from Table 2, mothers’ means for the two scaleswere in the normal range (M = 10, SD = 3).

Mothers’ Psychopathology

The Minnesota Multiphasic Personality Inven-tory (MMPI, Dahlstrom et al., 1975) was used to as-sess mothers’ psychopathology according to the pro-cedures described in the manual. The MMPI hasbeen widely used to assess many well-known neuroticand psychotic behavior manifestations in adults. Nor-mal scores are hypochondria (M = 8.92, SD = 4.88),depression (M = 21.55, SD = 4.69), hysteria (M =22.53, SD = 6.00), psychopathy (M = 19.89, SD =5.34), paranoia (M = 11.43, SD = 3.15), psychostenia(M = 17, 21, SD = 8.92), schizophrenia (M = 18.42,SD = 8.92), and hypomania (M = 20.00, SD = 4.91).Mean scores of mothers in this study were in the nor-mal range (see Table 2).

Mothers’ Parenting Stress

Mothers completed the Parenting Stress Index(PSI, Abidin, 1986) at home. The PSI is a screeningand diagnostic instrument designed to assess the rel-ative magnitude of stress in the parent–child system.

The mother is usually asked to complete the question-naire because she is assumed to be the most knowl-edgeable parent concerning the pressures and stres-sors present in the entire parent–child system. The120-item questionnaire (each item is rated by the par-ent on a 5-point scale) reflects areas of stress relatedto the child (e.g., hyperactivity, mood, demanding-ness) and to the parent’s own functioning (e.g., mar-ital stress, social isolation, role restrictions). Severalprevious studies have reported good concurrent, con-struct, and discriminant validity (Abidin, 1986). Theauthor has suggested that parents obtaining a totalscore above 245 should be offered referral for profes-sional consultation.

Assessment of Mothers’ Physical Health

Mothers completed a general information ques-tionnaire to describe the number of personal hos-pitalizations during the previous 5 years (exclud-ing childbirth), the number of chronic illnesses, andthe number of medical consultations. These numberswere added in order to obtain a physical health index.In average, mothers were in good physical health (seeTable 2).

Assessment of Mothers’ Social Contacts

Mothers completed a general information ques-tionnaire (Dumas & Whaler, 1983) to describe thefrequency of their weekly contacts with differentadults, including husband, mother, father, colleaguesat work, friends, brothers, sisters, physicians, thera-pists, and social workers. A social contact score wasgenerated by adding the frequency of weekly con-tacts (number of persons × frequency). A socialcontacts/satisfaction index was computed by dividingthe mother’s number of contacts by her perceptionof her degree of social isolation (as measured withAbidin’s, PSI isolation stress scale, Abidin, 1986). Weassumed that mothers’ perception of their social iso-lation was the result of the number of weekly socialcontacts mitigated by the degree of satisfaction withthe number of social contacts. For example, a per-son who has a limited number of social contacts butwho is satisfied with this situation would feel less iso-lated and would score higher than would a personwho is highly dissatisfied with a similar situation. Thecontacts/satisfaction index was used in the presentstudy as a measure of the mothers’ perception of theirsocial competence.




Assessment of Familial Initial Characteristics

Mothers completed a general information sheetto assess the family’s yearly income including publicassistance (yearly income/number of persons in thefamily), level of education and occupation, living ac-commodations (size of home or apartment/number ofpersons in the family), and family constellation (mar-ital status). Table 2 shows that all participants had alow socioeconomic status.

Assessment of Mother–Child Interactions. Eachboy was invited along with his mother to a labo-ratory installed in a neighborhood school to learnhow to use a computer learning program designedfor children. The lab task was designed to simu-late mother–child interaction during a school home-work situation. During a 30 min session, conducted inseparate rooms, the boys and their mothers learnedthe basic procedures of the Logo program (Papert,1972). Following the training session the boys werereunited with their mothers and asked to solve oneeasy and one difficult task (total = 30 min). Moth-ers were instructed to help their child whenever nec-essary. Videotapes of mother–child interactions wererecorded through a one-way mirror and were sub-sequently coded by two female observers. The cod-ing procedure used was developed by Dishion et al.(1983) and adapted by Charlebois et al. (1995). TheFamily Process Codes procedure includes several cat-egories to describe parent–child interactions (i.e.,positive, aversive, neutral, commanding, task related).

The two broad categories used in the coding ofthe mothers’ and the boys’ behaviors in the presentstudy were “being positive” (e.g., approving, reinforc-ing) and “being aversive” (e.g., disapproving, men-acing, attacking verbally, pushing or blocking accessto the keyboard). A mother–child interaction (a be-havior initiated by the mother or child followed bythe other’s response was recorded every 15 s. A ratio(n× 1, 2, 3 . . . . . . /total of behaviors) was computedfor the different boys’ and mothers’ behaviors. Relia-bility in the coding of boys’ and mothers’ behaviors byindependent observers was satisfactory with a meanalpha of .81 (minimum = .78, maximum = .87).

Assessment of Problem Improvement

The following measures represent changes overthe course of the first year of the prevention pro-gram. The analysis of problem improvement was lim-ited to the first year because 70% of the nonpersistersleft the program after the first year.

Changes in Boys’ Behavior

Changes in the boys’ prosocial behaviors,inattention–hyperactivity, aggressiveness, and anxietywas computed by subtracting T1 scores (PBQ eval-uations by the teacher at the end of kindergarten)from T2 scores (evaluations at the end of the firstgrade).

Changes in Boys’ Social Status

Subjects were administered the Peer Evalua-tion Inventory (Pekarik et al., 1974) in the classroomin November (T1) and again in May (T2) of thesame year. Children were assured that their responseswould remain confidential. They were given a ros-ter of photographs of all classmates and they wereasked to circle the pictures of the three classmates:(1) whom they liked most, who seemed to always un-derstand what was going on, and who helped others;(2) who started fights, disturbed the classroom themost, laughed at others, told lies, cheated, made upstories, and said that they could beat up other kids;(3) who were too shy to make friends, who were sadand did not want to play with the other kids, whostayed alone in a corner, and who had fewer friends.The assessment procedure was validated for a French-Canadian population (n = 560 boys and 555 girls ingrade 1; n = 618 boys and 676 girls in grade 4; n = 882boys and 818 girls in grade 7) by Schwartzman et al.(1985). It has proven to reliably determine acceptanceby peers in children’s social groups (Kupersmidt et al.,1990). Item scores were standardized into Z scoresindicating the boys’ social status in their referencegroup. Changes in social status were computed foreach child by subtracting the Z scores at T1 fromthe Z scores at T2. An increase of popularity and adecrease of fighting indicated improvement in socialstatus.

Changes in Mother–Child Interactions

Mother–child interactions were recorded accord-ing to the procedures and conditions described ear-lier 1 year after the beginning of the intervention andthe same coding procedure was used. A change scorewas computed by subtracting observations (motherpositive, mother aversive, son positive, son aversive)at T2 from observations made at the baseline assess-ment (T1).




Assessment of Persistence: The Dependant Variable

Number of sessions (maximum of 63) attendedby the mothers and the boys served as the depen-dent variable (i.e., persistence). Attendance recordsshow that 16.7% of participants were present at 0–10 sessions; 16.7% at 11–20 sessions; 5.6% at 21–30sessions; 8.4% at 31–40 sessions; 8.4% at 41–50 ses-sions and 44% at 51–63 sessions over the 3 years ofthe program. The correlation between the boys’ andmothers’ participation was high (r = .95).

Intervention Program

The intervention for boys included two com-ponents: social skills training and self-regulationtraining. These components are described elsewhere(Charlebois, 2000; Charlebois et al., 1999) and areonly briefly mentioned here. Adjustments in the con-tent and procedures were made for each year of theprogram in order to meet the boys’ developmentalneeds. The parental support and skills training facet ofthe multicomponent program was divided into threephases over a 3-year period. The first phase consistedof establishing a collaborative relationship and reduc-ing resistance. It was assumed that starting the pro-gram with a concrete activity would facilitate bondingto the group and the establishment of a collaborativerelationship. During the second phase parents wereinvited to cooperate with trainers in the preparationand delivery of the boys’ training program. Finally, thethird phase was devoted to group problem solving.

The main objective of the intervention in theschools was to create an alliance with the school di-rectors and the teachers to entice long-term collab-oration in the project. To achieve this, the interven-tion was based on the following principles: (1) providesupport in coping with stress (DeVito, 1993); (2) en-courage the creation of teacher support groups ineach school (Weinstein et al., 1991); (3) use an em-powerment approach in the decision-making process(Hayes, 1992); (4) provide information on disrup-tive behaviors, classroom management of disruptivebehaviors, classroom self-regulation, and problem-solving strategies. Details of the content and proce-dures for parent and teacher support are availableupon request from the authors.

Conformity Assessment

A conformity assessment was conducted forthe three components of the program to determine

whether or not exposure to the intervention (contentand duration), and the trainers’ management strate-gies conformed to the intervention plan (McGrawet al., 1989; McGraw et al., 1994; Schneider, 1992).Various methods were used to evaluate the imple-mentation of the different components of the inter-vention program. Trainers recorded attendance forevery session. Exposure to the intervention (contentand duration) and trainers’ management strategieswere assessed using observations and trainers’ re-ports. Notwithstanding necessary adjustments, obser-vations, trainers’ reports, and weekly supervisions bythe program director confirmed that the training com-ponents were generally implemented as planned.

RESULTS

A hierarchical linear regression analysis wasperformed to identify the potential predictors ofpersistence in this early-age targeted longitudinal pre-ventive intervention. Prior to the execution of thisanalysis, variance and independence of the differ-ent predictors were verified. Based on correlationanalysis, variables excluded from the analysis were(1) changes in boys’ aggressiveness, anxiety, andprosociality; (2) changes in mothers’ aversive beha-vior; and (3) mothers’ social contacts before thebeginning of the program. Changes in boys’ aggres-siveness, anxiety, and prosociality were excluded be-cause the correlations between the change scores andattendance to the program were low and not signifi-cant at the p < .05 level (aggressiveness: r = −.118;anxiety: r = −.23; prosociality: r = −.007). Similarly,changes in mothers’ aversive behavior and mothers’social contacts were excluded because the correla-tions between the change scores and attendance tothe program session were low and not significant atthe p < .05 level (mothers’ aversive behavior, r = .02;mothers’ social contacts, r = .06).

A normal distribution was observed for all vari-ables included in the hierarchical linear regressionanalysis. As can be seen from Table 3, the variables in-cluded in this analysis were independent as indicatedby low and nonsignificant correlations among the pre-dictors. Table 3 also shows that the predictors includedin the analysis were significantly correlated with thenumber of sessions attended. Interaction variables(i.e., mothers’ and sons’ positive and aversive behav-iors) observed before the beginning of the interven-tion program were entered in the first step of theanalysis. Changes in mother–son interaction (i.e., the




Table 3. Correlations Between Predictors and Attendance (n = 59)

Variables 1 2 3 4 5 6 7

1. Attendance (3 years) — .31∗∗ .32∗∗∗ .27∗ −.29∗ −.29∗ −.31∗∗

2. Mother positivea — .12 −.01 .03 −.03 .023. Son positivea — .08 .05 −.07 −.024. Son aversiveb — −.04 −.12 .075. Son helpsb — .03 .096. Son fightsb — −.067. Son inattentiveb —

aAssessed before the beginning of the program.bImprovement 1 year after baseline.∗ p < .03. ∗∗ p < .01. ∗∗∗ p < .005.

difference between the frequency of mothers’ or sons’positive and aversive behaviors observed 1 year afterthe beginning of the intervention and the frequencyof these behaviors observed at baseline) were enteredin the second step of the analysis. Changes in the boys’social status (i.e., differences between peer nomina-tions with regards to help-giving and fighting 1 yearafter the beginning of the intervention and peer nom-inations at baseline) were entered in the third step ofthe analysis. Changes in the boys’ behaviors assessedby the teachers (i.e., difference between scores 1 yearafter the beginning of the intervention and scores atbaseline on inattention, and hyperactivity) were alsoentered in the third step of the analysis.

Results of the hierarchical regression linearanalysis, presented in Table 4, indicate that thebest prediction (R= .69; R2 change = .24, p < .002)was achieved at the third step when both baseline

Table 4. Hierarchical Linear Regression Analysis to Test PotentialPredictors of Persistence in an Early-Age Targeted Longitudinal

Preventive Intervention

Variables β R R2 change

Step 1 .42 .18∗∗

Positive (mother)a .27Positive (boy)a .29∗

Step 2 .49 .06Positive (mother)a .28∗

Positive (boy)a .26Aversive (boy)b .25

Step 3 .69 .24∗∗∗

Positive (mother)a .29∗

Positive (son)a .25∗

Aversive (boy)b .24Helps (boy)c −.26∗

Fights (boy)c −.25∗

Inattention hyperactivityc −.32∗∗

aAssessed before the beginning of the program.bImprovement in mother–child interactions 1 year after baseline.cImprovement in boys’ behavior 1 year after baseline.∗ p < .05. ∗∗ p < .01. ∗∗∗ p < .002.

interaction scores and changes in the boys’ behaviorswere included in the analysis. Significant predictors ofpersistence in the program were mothers’ positive be-havior before the beginning of the program (β = .29,p < .05); sons’ positive behavior before the beginningof the program (β = .25, p < .05); reduction in boys’provision of help to peers (β = −.26, p < .05); reduc-tion in boys’ fighting (β = −.24, p < .05; and reduc-tion in boys’ inattention (β = −.32, p < .01).

DISCUSSION

Attrition or loss of cases has always representeda major obstacle in the search for effective preventiveintervention programs because it limits the validity ofthe intervention and the generalizability of the con-clusions. Considering the participants’ characteristicsselected for the present multimodal ETLP and thenature of the program the participants were offered,the present study showed that predictors of persis-tence in the program were mothers’ and sons’ pos-itive behaviors in mother–son interactions observedprior to the beginning of the program, improvementin boys’ peer-rated fighting scores and an improve-ment in boys’ teacher-rated inattentive–hyperactivebehaviors. Notwithstanding these results, one couldargue that the intervention was delivered to a sub-group (those who persisted) that did not seem toneed the intervention because they were character-ized by a positive mother–son relationship at thepretest. However, a comparison of those with a posi-tive mother–son relationship in the intervention andthe control groups, confirmed the relevance of the in-tervention for the persisters. An analysis of variancecontrolling for mother–son positive relationships atpretest showed that the persisters had a significantlysuperior academic achievement (p < .002) than thecontrol group after 3-year intervention (Charlebois,2001). A reduction in peer-rated help nominations




also contributed to the prediction. This is a puzzlingresult that will be discussed later.

The first result confirms findings from previ-ous studies (Forehand & McMahon, 1981; Patterson& Forgatch, 1995) that showed that the quality ofthe parent–child relationship is an important fac-tor in treatment persistence and progress. Similarly,Braswell et al. (1997) reported that higher atten-dance was associated with reports of more adaptiveparental discipline practices at baseline. These resultsare clearly indicative of a relationship between, onone hand, participants’ personal and interpersonalpredisposition and, on the other hand, different inter-vention content and procedures. Kazdin and Wassell(1999) showed that perceived relevance of treatmentis one of the principal obstacles to change in treat-ment. Although this was not measured in the presentstudy, it seems reasonable to hypothesize that themothers who were more mobilized by the type of sup-port offered by the program and thus persisted. It isalso possible that mothers who had a positive rela-tionship with their son could have conveyed to himthe confidence that persisting in the program wouldbe beneficial and the son’s positive response couldhave reinforced the mother’s own persistence in theprogram.

Findings from the present study also show thata predisposition to engage in a given program is notsufficient to explain persistence. The best predictorof persistence was a reduction in the teachers’ ratingof inattention–hyperactivity after the first interven-tion year. Improvement of the boys’ attention in classwas a major objective of the intervention program.Peers’ perceptions also improved for boys who per-sisted as indicated by a significant reduction of nom-inations for fighting. The interpretation of a relation-ship between a reduction in peer-rated help scoresand persistence is more puzzling. Is it possible tobe perceived by peers as less aggressive (i.e., fight-ing) and as less sociable (i.e., helping others) at thesame time? A possible explanation could be that dis-ruptive children who persisted in the program be-came more self-controlled and, as a consequence re-duced the overall frequency of their interactions withpeers, both negative and positive. How would thatexplain the relationship with persistence? It is not un-reasonable to think that the progress in the child’sdisruptive behavior, as conveyed to the mother bythe teacher and to the child by the peers, encour-aged the mother and the child to persist in the pro-gram in the hope of further improvement in prosocialbehavior.

Limitations and Guidelines for Future Research.Findings from the present study showed that predic-tion of persistence was improved when measures ofpositive change in the participants’ problems wereconsidered in addition to factors present at the be-ginning of the program. As underlined by Kazdin andWassell (1998, 1999) these findings confirm the impor-tance of ongoing assessment of progress during the in-tervention to advance knowledge on the factors thatpredict persistence in intervention programs. Findingsalso support the point made by Eddy et al. (1998) re-garding the importance of unbiased and specific mea-sures of intervention change (i.e., peer nominationsand teacher ratings in the present study). Despiteits contribution, the present study also raises severalquestions that remain to be answered.

First, can the findings be generalized to all ETLPprograms? The identification of a totally different setof predictors than those found in SOT raises the pos-sibility of different predictors for different programsand different selected participants. This is consistentwith Mash’s analysis (Mash, 1999) suggesting that,notwithstanding the possibility of some overlap, pre-dictors of attrition and strategies to minimize it couldbe different for the prevention of different childhooddisorders. The opportunity to document this issue isoffered, without great cost, by the analysis of predic-tors in previous or ongoing ELTP programs. A re-view of preventive experiments for Oppositional De-fiant and Conduct Disorders conducted by Tremblayet al. (1999) showed that several studies alreadyhave the necessary information to allow for such ananalysis.

Second, the present study could not provide in-formation on the characteristics of the families whodid not accept to participate and therefore cannotpropose guidelines on the type of intervention thatcould be more appropriate for meeting their needs.Notwithstanding the extra efforts that were made toreach these families (i.e., sending a research assistantto meet the parents at home) the research agendadid not permit investing more time and energy tolearn more about these families. We found that someof these parents were very difficult to contact (i.e.,never returned phone calls, refused to answer the dooron house visits). We suspect that these families wereamongst the most impoverished, socially isolated, andmistrustful toward anyone who could be perceived asa social service agent (i.e., a social worker, or an in-vestigator for child abuse or neglect). If such were thecase, an individual approach by a social service agentwho would take the time to establish a significant




relationship with the parents would seem to be moreappropriate.

Third, what could be done in order to preventpremature termination? Personal contacts with sev-eral researchers in the field of preventive intervention(Normand et al., 2000) suggested the following rules:(1) maintain personal contact (contact should be priv-ileged with low socioeconomic status families) fromthe beginning to the end of the program. Maintaina warm and involved relationship with the familyeven if parents or children stop attending the ses-sions; (2) eliminate obstacles (e.g., offer babysitting,transportation); (3) establish a significant relationshipbetween staff and participants and also between par-ticipants themselves. In certain occasions, anotherparent might be more effective in maintaining con-tact than would program personnel.

Finally, the present findings could leave the im-pression that this study offers little to minimize thedrop out rate of families who have the greatest needfor treatment. In order to better understand thecontribution of the present study; however, it willbe important to consider the following points. Wesuspect that the mismatching of social skills leveland group sessions could have been, for some ofthe mothers, a major factor of attrition in this pro-gram. Most studies take for granted the relevance ofprogram content and procedures proposed to par-ticipants and do not plan for a differential match-ing of participant needs and program components(Charlebois et al., 1999; Kazdin & Wassell, 1999).Cunningham et al. (1995) also showed that when par-ents were offered a choice from different modalitiesof a prevention program, 69.6% refused to partici-pate in the group sessions, 43.5% in individual sup-port sessions, and 40.4% in information sessions. Al-though parents could be attracted by a preventiveprogram’s objectives, there are indications that par-ents’ perception of the relevance of the interventionwill strongly influence their motivation to persist ina program. Therefore, the documentation of the mo-tives of participants who accept or refuse to partic-ipate to ELTP programs could be as important asidentifying the factors that predict persistence in theseprograms.

ACKNOWLEDGMENTS

We thank the Conseil Quebecois de la Recherchesociale, the St-Jerome, and Ste-Therese school boards,the Regie Regionale des Laurentides, the CLSC

Arthur Buies, as well as the parents, children, andteachers who made this research possible.

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