J . ment. Defic. Res. (1977) 21, 273 273

POST SCHOOL ADJUSTMENT OF THE MENTALLYRETARDED: A CRITICAL NOTE ON THE NEBRASKAN

LONGITUDINAL SURVEY OE BALLER, CHARLESAND MILLER

R. JACKSONKing Alfred's College of Higher Education, Winchester, Hants, England

INTRODUCTIONThere can be little doubt that one of the most frequently cited and most

influential studies which have examined the occupational and social adjustment ofthe mentally retarded is the longitudinal survey conducted in Lincoln, Nebraska,by Bailer in 1935, which was subsequently followed up by Charles in 1950, Miller in1961 and Bailer, Charles and Miller in 1964 (Bailer, 1936; Charles, 1953; Miller,1965; Bailer, Charles and Miller, 1967). The average age of the sample was twenty-seven in 1935, forty-two in 1950 and fifty-six in 1964. (It should, however, be notedthat the size and composition of the sample changed during the survey period.) Inthe years since its publication the Nebraskan survey has come to acquire withinNorth America and Britain the status of a classic and definitive work. This paperseeks to provide an answer to two questions. First, "Is that reputation justified?"Second, "To what extent is it possible to generalise on the basis of the findingsobtained in this survey?"

An examination of the following extracts which are taken from a randomselection of reviews of past adjustment studies makes it clear that the findings of thissurvey have been taken as convincing support for the proposition that the ntiajorityof mentally retarded adults do successfully adjust both in employment and in thecommunity.

"Briefly, the studies of Fairbanks, Bailer and Kennedy present the followingconclusion(s): 1. The majority of higher grade mentally retarded persons willmake an acceptable adjustment in their communities." (Goldstein, 1964.)"The work of Bailer, Charles and Miller is the best example we have of alongitudinal follow-up of a sample of eommunity-dwelling persons identifiedas retarded. In many respects it parallels and confirms the reports of Kennedy,although in important respects it differs. Both agree in demonstrating a highproportion of successful community adjustment in a group initially marked forsocial failure." (Cobb, 1972.)". . . studies dealing with retardates over age 25 consistently reported highrates of employment, generally over 90% for mildly retarded males (Bobroff,Ferguson, Bailer and Kennedy) and around 50% for mildly retarded females."(Conley, 1973)."Charles (1953) showed that the majority of a group of 151 handicappedpeople leaving opportunity classes in the United States were still functioningadequately after flfteen years. The vast majority were still employed and the

Received 11 th May, 1977

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most critical comment made was that the incidence of social misdemeanourswas above average." (Brown, 1975.)If it can be successfully demonstrated that, contrary to general opinion, the

Nebraskan survey does not provide as reliable an indication of the future adjustmentpotential of the retarded as is commonly supposed, and if it can be shown that thesurvey is much less optimistic in tone than is frequently assumed, then it may leadto a belated recognition of the fact that we know much less about the post-sehoolcareers of the retarded than is usually thought. In order to challenge the validity ofsome of the general conclusions which have been drawn both by the authors and bysubsequent reviewers from the survey's findings, it is necessary to undertake a carefulre-examination of the original data. Discussion, therefore, will be focussed on threemain areas: (1) intelligence, (2) self-support, and (3) social status.

(1) IntelligenceIn the first survey Bailer confidently claimed that the clinical diagnoses of the

original sample of 206 opportunity room children indicated that "they were definitelydeficient in mentality." (Mean IQ,: males 60.50, females 59.00) (p. 190). However,a strikingly different picture emerged in the first follow-up survey. On the basis ofintelligence test reeords and individual social data Charles (1953) placed his subjectsinto four categories: (1) only twenty per cent were clearly mentally deficient,

(2) ten per cent were borderline in ability but had become "fairly well adjusted andself suflicient members of society", (3) sixty-five per cent gave evidence of beingdull-normal or average in ability, and (4) five per cent had life-long handicaps thatmade accurate and valid testing difficult or impossible. It is important to stress thatCharles' definition of intelligence was largely based on a judgement of a subject'ssocial achievement. We will return to the dubious merits of this procedure later.

Using the Wechsler-Bellevue Adult Intelligence Scale for all but one of thetwenty-four subjects actually re-tested in 1950, Charles found marked gains in IQ,scores. For the twenty subjects whose IQ, data were eventually used, the mean dif-ferences between the Binet and Wechsler scores were fourteen points for the Verbal,thirty points for the Performance and twenty-three points for the Full Scale. AlthoughCharles aeknowledged that the results of the two different tests were not strictlycomparable and that at the low end of the scale the Wechsler test tends to give highscores, he stated that the differences obtained were greater than could be accountedfor on that basis or attributed to the natural tendency for extreme scores to regresstowards the mean. In Charles' opinion the changes in IQ_scores did not represent a realincrease in intelligence but reflected the inadequacy of the 1916 test and errors intesting arising from such problems as language barriers, social and economic depriva-tion. To underline his argimient Charles cited Wechsler's own criticisms of the Binettests for use with adults, namely, that they laeked interest and appeal for adults sincethey were designed and standardised for children and that they depended too stronglyon quickness of response and verbal fluency.

It is worth noting that a quarter of the children in the original sample wereof foreign parentage (i.e. Russian-German, Cerman, Bohemian, Italian and Jewish).

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While Bailer observed that many of these parents did speak some English, he foundthat their children spoke English "with varying degrees of facility" (p. 195). Thepossible effect that this linguistic handicap may have played on the test and schoolperformance of these pupils was noted by Charles:

"Both of the principal criteria of deficiency, scores below 70 IQ, on the 1916Binet and inability successfully to carry the usual academic work in school,were highly verbal in nature, and the subjects demonstrated poor ability in thisarea even on the Wechsler in the present tests." (p. 65.)Charles concluded that the social data obtained in the 1935 and 1950 studies

reinforced the impression that "a sizeable segment of the population were 'dull' rather than'mentally deficient'." (p. 65.)

The accuracy of Charles' own conclusion is itself suspect as only twenty-fourout of the 127 located survivors of the original sample were re-tested! This smallnumber appears to have resulted from the fact that (a) the interviewer only requestedsome of the subjects to take the test, and (b) many of the subjects chosen refused toallow the interviewer to administer the test. No indication is given in Charles' paperhow this original selection was made. The reader is presented, however, with thefollowing rather unpersuasive explanation for the procedure adopted.

"When it was determined that this was the total number of subjects that couldbe re-tested as a part of the present study, it was noted that a selection of 20 ofthese would constitute a representative sample of the total population." (p. 64-5.)This explanation is plainly ambiguous. A total of twenty subjects might well

be sufficient to provide a representative sample. The question remains, however,were the twenty subjects actually chosen in this particular study representative?And, why were the other four re-tested subjects excluded ?

In the absence of IQ, data for the overwhelming majority of the sample in theflnal study, an estimate of present level of intelligence was made from "behaviour data—e.g. if a man had been operating his own business successfully for some years, hewould be judged at least 'average' in functional ability." (p. 251.) It is difficult tosee how this procedure, which repeats the one adopted in Charles' study, can bejtistifled. One of the aims of the survey was to find out whether there was a relation-ship between measured intelligence and funetional ability, not to presume that sucha relationship existed!

On the basis of estimates of subjects' ability. Bailer et al. concluded that thesample had maintained or exceeded in 1962 their improved levels achieved betweenthe 1935 and 1950 studies. They noted that at least one quarter of the subjects couldnot be described as mentally deficient in any way, while nearly half were belowaverage or mildly defieient but not seriously retarded. They then sought for reasonsto explain this improved status. While similar explanations were advanced to thoseproposed by Charles in the 1950 study, they were given a different emphasis. First,-it was suggested that the improvement in "ability" with the passage of time mighthave resulted from the slower intellectual growth of the subnormal subjects. Second,the possibility is entertained that many of the subjects might have lacked environ-mental stimulation in their early years and that their later improvement resulted

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from their learning experiences in the outside world. It is significant that the thirdsurvey, which Bailer co-authored, played down the possibility which was so stronglyadvanced by Charles that the large proportion of dull-normal subjects revealed inthe 1950 study resulted from the application of an inadequate test and from errorsin testing.

A careful examination of these different studies must leave serious doubts in thereader's mind as to whether the original sample was composed entirely of mentallydefieient subjects as Bailer had confidently affirmed. If the sample did indeed containa significant proportion of dull-normal adults then it is clear that one can draw nogeneral conclusions from the Nebraskan survey as to how mentally retarded adultsare likely to adjust either in employment or in the community!

(2) Self-supportIt will have been apparent from an examination of the extracts presented

earlier that the findings of the Nebraskan survey have been taken as convincingproof that most subjects diagnosed as retarded whilst of school age are likely to makeadequate adjustment in employment. Closer inspection of the survey data prov^idesscant support for this view. For example, those who have cited the findings of theBailer study as portraying an optimistie employment future for the retarded haveeither misunderstood or overlooked Bailer's own assessment:

"In one respect it is not too bright a picture to see that sixty-one per cent ofthis group are unable to hold steady employment and have histories of shortterm (less than six months) and infrequent occupation. On the other hand,when their mental status, and the original prognoses for them, is considered,the fact that thirty-nine per cent have held jobs with a reasonable degree ofsuccess is of some consequence and furnishes at least an improvement upon thestatus which an earlier prediction would have suggested." (pp. 235-6)It is elearly important that Bailer's qualified optimism should be set within the

context of the generally low expectations that existed in the twenties and thirties asto the occupational potential of the mentally retarded.

Perhaps one of the most erucial findings of the whole survey and one that hastended to attract most attention is the claim that the employment status ofthe subjects under review improved with time. Bailer et al. provided data toshow that in 1935 twenty-seven per cent were found to be economically self-supporting, in 1950 the percentage had risen to thirty-six per cent, and by 1964 ithad reached sixty-five per cent. Incidentally, economic self-sufficiency was narrowlydefined to mean that a subjeet was not on the roll of a relief agency, institutionalisedor dependent on relatives. A number of points need to be made about the figurespresented in Table 1. First, there is the obvious fact that the percentages do not relateto a sample of constant size. With the passage of time the original sample of 206 hadcontracted to 151 in 1950 and to 109 in 1964.The halving in size of the originalsample must raise some doubts as to how representative the final sample of 109 was.The authors recognised this problem and stated that one way of judging its repre-sentativeness was to compare the original total group and the current group on

R. JACKSON 277

Table 1

Analysis of self-support: 1935—1950—1964

Male Female TotalNo. Total % Mo. Total % No. Total %

Wholly self-supporting 28 113 25 21 69 30 49 182 27(Bailer, 1935)

Entirely self-supporting 16 49 33 13 31 42 29 80 36(Charles, 1950)

Entirely self-supporting 38 61 62 33 48 69 71 109 65(Bailer, Charles andMiller, 1964)

various characteristics (i.e. IQ,, sex and race/ethnic origin). They concluded thatthe "subjects of the present study seemed to be representative of the original popula-t ion." [my italics] (p. 249.) This conclusion is based on the confident but dubiousassumption that the selection of these partieular characteristics was both sufficientand relevant.

Seeond, the dramatic improvement in the employment status of the subjectsmay be more apparent than real. Tha t is to say, it is quite possible that all or mostof those subjects found to be "wholly self-supporting" in 1935 remained economicallyself-sufficient throughout the survey period! In other words, forty nine out of theseventy-one subjects (i.e. 70 per cent) described as "economically self-supporting" in1964 were also self-sufficient in 1935. As a proposition this does not seem unreasonable.I t is a possibility surprisingly ignored by the authors and later reviewers. Thus themarked contraction in sample size over the follow-up period may have had theeffect of exaggerating the small actual increase in the number of subjects found to be"self-supporting" in 1964. Some support for this interpretation comes indirectlyfrom the survey itself. The tendeney was noted for "adjusted" subjects to remainin their home neighbourhood, where they were more easily located (Bailer definedan "adjusted" subject as someone who was wholly self-supporting and had norecord indicating "breaches of the law or of violations of accepted standards oiethics"). I t was also found that the poorly adjusted tended to be more geographicallymobile and thus more diffieult, if not impossible, to locate. In other words, the Nebras-kan survey may merely demonstrate a relationship between adjustment and detection.

Third, the duration of the study paralleled profound changes in the Americaneconomy, from pre-war recession in the thirties with exceptionally high levels ofunemployment, through the war years with chronic labour shortage to post warboom in the sixties with continuing low levels of unemployment. Thus in interpretingthis data one eannot ignore the effeet of changing employment opportunities.

Acceptance of one or all of these points would be sufficient to throw some doubton the claim that the majority of retarded in this survey satisfactorily adjusted in employ-ment. But what is meant by successful employment adjustment? Heber and Dever(1970) have rightly drawn attention to the fact that eighty per cent of the jobs held

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by the males in the 1964 follow-up were in the unskilled and semi-skilled categories,where wage rates tend to be low. They point out that while it may be true that themajority of the retarded were self-supporting, existence at or below poverty level ishardly the best of all possible worlds! In other words, self-support in this and othersurveys should not be taken as the sole criterion of suecessful employment adjustment.

(3) Social statusThe belief that the Nebraskan survey provides clear evidence that the majority

of retarded achieve a satisfactory level of social adjustment also has little basis in fact.Bailer's own eonelusion is unambiguoixs and scarcely optimistic:

"When one tries to form a eomposite impression of the social status of the 206men and women followed up in this investigation, it is doubtful whether asmuch hopefulness is warranted as some studies of other groups imply." (p. 239.)It must be remembered that one of Bailer's main concerns in presenting his

evidence was to challenge the popular belief current at the time that "deficientmentality practically precludes social usefulness". By showing that some subnormalsubjects were capable of providing a living for themselves and were able to get alongwith their fellow men, he hoped to dispel the excessively pessimistic prognoses thatwere held for the retarded. A closer inspeetion of Bailer's own findings may helpexplain some of the reasons for his muted optimism. Relevant findings from theother studies are also presented.

Law conformity: In comparing the incidence of anti-social conduct between thesubnormal group and the controls of normal intelligence. Bailer found three to seventimes as many breaches of the law charged to the sub-normal group (see Table 2).This pronounced difference is interpreted by Bailer to signify the greater difficultyencountered by the subnormal subjects in shaping their conduct to conform to thelaws and social standards of the community. He was anxious to point out, however,that hasty generalisations about the possibly inherent anti-social nature of sub-normal persons were not warranted. Bailer also commented that it was perhapssurprising that the extent of misconduct was not even more pronounced when heldagainst the background of less stable home environments, the greater diffieulty insecuring employment and the more frequent residence in undesirable neighbourhoods.

In the 1950 study Charles noted that thirty of the Lineoln residents had beeninvolved in law violations since 1935. This comprised about forty per cent of theresident subjects, nearly sixty per cent of the resident males alone. About a quarterof these violations were traffic offences, the rest civil. Drunkenness accounted for halfof the civil cases. The findings of this study need to be treated with some care as

Table 2Conduct records of subnormal and control subjects (Bailer,. 1935)

Subnormal subjects Control subjectsMale(126) Female{80) Total{206) Male{126) Female{80) Total{206)

Juvenile court 32 26% 17 23% 49 25% 6 5% 2 3% 8 4%Policecourt 31 25% 4 6% 35 18% 12 10% 1 1% 13 6%

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records were obtained for the residents of Lincoln only. In the final survey period,Bailer et al. observed that the subnormal group was generally law-abiding. Less thanten per cent of the group had convictions for civil offences and most of these were"typically lower class (e.g., drunk and disorderly) rather than vicious or trulyanti-social", (p. 310.) Although the authors acknowledged the fact that the "success-ful" subjects were likely "to have stayed in one community rather than havingdrifted about", they overlooked the real possibility that the large unlocated groupmay have presented quite a different picture as far as law conformity is concerned.

Marital status: In the first study Bailer drew attention to two interesting findings.First, the girls of the subnormal group married in a much larger percentage of casesthan the boys (fifty-nine per cent: thirty-three per cent). He suggested that thisfinding might lend some support to the assertion that "girls marry to secure economicsupport while ihe men do not marry on account of the same economic factor."Second, a significant difference was noted between the average age of marriage ofthe females of the two groups. Subnormal girls tended to marry at just under twenty,while the girls in the control sample tended to marry at twenty-one and-a-half.This finding is of particular interest because of the greater apparent risk of maritalbreakdown when one or both spouses marry young (Fletcher, 1966). Thus the factthat so many of the subnormal girls had married and had married young should notnecessarily be regarded as evidence of successful adjustment. It is revealing to noteihat in the 1964 study it was found that "the divorce rate was from two to ten timesabove the national average in the two [subnormal] groups". It was also noted thatthe subnormal subjects had less success than other subjects "in getting and keepingmates and were consequently more likely to be living alone." Eighteen per cent ofthe subnormal group had never married.

Mortality: One important finding in the 1964 study that has received surprisinglylittle attention is the stark fact that nearly one-third of the "loeated" subjects haddied! Illness rather than accident was the cause of death in ninety-five per cent ofthe cases. This contrasts with the pattern observed in the Charles' study, where therewas an unusually high accidental death rate—thirty per cent in comparison to thesix per cent expected. No attempt is made to explain the high death rate, yet whatmore vital statistic of adjustment can there be ? Was the high rate due to (a) a lack ofself-care, (b) unhealthy living conditions, (c) unsatisfactory diet, (d) lack of mediealattention, (e) accident-proneness, (f) low wage rates limiting subjects' ability topurchase adequate food, housing and medical care, (g) a constitutional defect of thesubnormal ?

Even the most cursory examination of the Nebraskan survey makes it clear thatin terms of law conformity, marital status and mortality, the subnormal group didmarkedly less well. It is difficult to see, therefore, how the findings of this surveycan be interpreted as providing support for the proposition that most adult retardedachieve a satisfactory level of social adjustment. Indeed in the final paragraph oftheir paper. Bailer et al. sound a distinctly sombre note by highlighting some of the

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adjustment problems that are likely to confront the retarded as they grow older.For example, (1) How will the subjects handle the rapid technological changesthreatening many of their jobs^—particularly service occupations? (2) Will theincreased age level of the subjeets compound the problem of retraining or of findingnew jobs? (3) Will many of the subjects become public charges in their old age asthey have no financial resources beyond social security ? (4) What will happen to thehigh percentage who live alone when eonfronted with the weakness and illness thataccompany old age ? (5) And who will eare for them ?

One reason why these important questions have tended to be ignored for solong is because of the belief or myth, endlessly repeated in most research reviews,that the majority of the retarded do adjust both in employment and in the community.Constant repetition of this belief has encouraged some writers to conclude that littlewould be gained from undertaking further longitudinal studies. Other writers clearlyfeel that those longitudinal studies already conducted provide sufficient informationto make further exploration pointless. Such an attitude is expressed in the followingpassage taken from a researeh review by Tizard (1965):

"The Bailer-Charles study and similar investigations carried out of the aftercareers of institutional defectives make further purely descriptive studies oflittle general interest. . . it can indeed be said that half a century of investigationhas done little more ihan eorrect the false ideas that have been put forwardduring the same period."This extract, perhaps not surprisingly, is also quoted by Balier et al. in support

of their view that replications of simple, descriptive longitudinal studies wouldprobably not be very rewarding.

While the inductive process is an accepted form of determining general laws orformulating statements of universal applicability, there can be little justification inattaching so much general predictive significance to a single survey conducted on arapidly dwindling sample drawn from an obscure Nebraskan town during one of themost turbulent periods in American economic history.

To the extent that past investigations have demonstrated that some retardedare capable of holding down a job in open employment and are able to functionindependently in the community, they have, as Tizard indicates, correeted certainfalse ideas about the potential of the retarded that once existed. However, we havenow reached a point where it may be necessary to redress the balance by correctingfalse ideas that exist at the present time. The unduly pessimistic outlook whichcharacterised thinking in the twenties and thirties would seem to have been replacedin the sixties and seventies by a degree of optimism that is searcely warranted from acareful examination of available evidence.

One point of clarification should be made. The writer is not suggesting thatmost adult retarded fail to adjust in employment and in the community. What isbeing argued is that we still do not know whether the majority adjust or not! Further, ourlack of knowledge will continue for as long as we remain dependent on (a) assessmentsof little predictive value which are based on the results of short-term surveys, (b)the findings obtained from a few, dated longitudinal surveys which are of more

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historic interest than contemporary relevance, and (c) impressionistic evidencederived from teachers, careers offieers, social workers and other professional staff.

The aim of this paper has not been simply to highlight certain shortcomings inone overrated investigation but to draw attention to the obvious defects in thedescriptive and interpretive skills of many past reviewers. An examination of therelevant literature on post-school adjustment of the mentally retarded over the lasttwo decades provides a good illustration of the way in which a myth can be created,fostered and eventually transmuted into one of the conventional widsoms of ourtime. Social scientists perhaps need reminding that one of their principal functionsshould be the breaking, not the making, of myths!

REFERENCESBALLER, W . R . (1936) A study of the present social status of a group of adults, who, when they

were in elementary school, were classified as mentally deficient. Genet. Psych. Monog. 18,165.

BALLER, W . R . , CHARLES, D . C . and MILLER, E . L . (1967) Mid-life attainment of the mentallyretarded: a longitudinal study. Cenet. Psych. Monog. 75, 235.

BROWN, R . I. (1975) Vocational and social training. In: WEDELL, K . (Ed.) Orientations inSpecial Education. London: John Wiley.

CHARLES, D . C . (1953) Ability and accomplishment of persons earlier judged mentallydeficient. Genet. Psych. Monog. 47, 3.

COBB, H . V. (1972) The Forecast of Fulfillment: A Review of Research on Predictive Assessment ofthe Adult Retarded for Social and Vocational Adjustment. Columbia University: TeachersCollege Press.

CONLEY, R . W . (1973) The Economics of Mental Retardation. Baltimore: The Johns HopkinsUniversity Press.

FLETCHER, R . (1966) The Family and Marriage in Britain. London: Penguin Books.GOLDSTEIN, H . (1964) Social and occupational adjustment. In: STEVENS, H . A. and HEBER, R .

(Eds.) Mental Retardation: A Review of Research. Chicago: University of Chicago Press.HEBER, R . F . and DEVER, R . B. (1970) Research on education and habilitation of the mentally

retarded. In: HAYWOOD, H . C . (Ed.) Social-Cultural Aspects of Mental Retardation. New York:Appleton Century Crofts.

MILLER, E . L . (1965) Ability and social adjustment at mid-life of persons earlier judgedmentally deficient. Genet. Psych. Monog. 72, 132.

TIZARD, J. (1965) Longitudinal and follow-up studies. In: CLARKE, A. M. and CLARKE,A. D. B. (Eds.) Mental Dejiciency: The Chdnging Outlook. London: Methuen.