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Further Observations on the Psychometric Properties of the Psychological Effectiveness Scale R. Olukayode Jegede

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Department of Psychiatry , University College Hospital , Ibadan, Nigeria Published online: 02 Jul 2010.

To cite this article: R. Olukayode Jegede (1976) Further Observations on the Psychometric Properties of the Psychological Effectiveness Scale, The Journal of Psychology: Interdisciplinary and Applied, 93:1, 137-140, DOI: 10.1080/00223980.1976.9921384 To link to this article: http://dx.doi.org/10.1080/00223980.1976.9921384

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Published as a separate and in The J o u m d o f Psychology, 1976, 93, 137-140.

FURTHER OBSERVATIONS ON THE PSYCHOMETRIC PROPERTIES OF THE PSYCHOLOGICAL EFFECTIVENESS SCALE*'

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Department o f Psychiatry, University College Hospital, Ibodan, Nigeria

Previous work by Poe and by the present writer have shown that the Psychological Effectiveness Scale (PES) has sufficiently high validity and reliability to justify continued research on the instrument. In an attempt to study further the psychometric attributes of the PES, 54 American men and women volunteer methadone clinic patients were assigned a wider range of rating tasks than had hitherto been used. The Ss rated themselves under six different instructions. Internal consistency reliability, measured by coefficient alpha, was in the .?Os in all ratings. The differences between the means of some of the ratings were significant a t the .O1 level. Average item-correlation (total minus item) was also high. These findings, consistent with the results of earlier work, confirm the reliability and construct validity of the PES.

The Psychological Effectiveness Scale (PES) was introduced by Poe ( 7 ) for the purpose of measuring "psychological effectiveness,'' a concept that combines elements of self-concept theory and Maslow's notion of selfactualization. In the present writer's pilot study (4) with 100 patients on a methadone maintenance program, many of the 50 items on the PES were modified by replacement of the more difficult words with simple ones within the range of the vocabulary of the patients. The modified version was also used in the present study. In one of his studies Poe (7) asked 93 college students to rate the following concepts: typical person, ideal person, abnormal person, and mentally healthy person. In another study Poe (6) obtained self-ratings of 136 college students. In both studies a coefficient alpha which was in the .90s was obtained. In Jegede's (4) pilot study mentioned above the Ss who were of lower socio-

* Received in the Editorial Office on March 11, 1976, and published immediately at Provincetown, Massachusetts. Copyright by The Journal Press. 1 This study was done while the author was at the Drug Addiction Research Unit, State University of New York Downstate Medical Center, Brooklyn, New York. The cooperation of both staff and patients is gratefully acknowledged.

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economic status than Poe's college students were instructed to rate the following: self, typical person, and abnormal person. The coefficient alphas obtained on these ratings were, respectively, .93, .95, and .95. The aim of the present study was to evaluate the reliability of the PES when Ss were given a wider variety of rating tasks.

The Ss were 54 male and female volunteers from the same population of methadone clinic patients in Brooklyn, New York, from which the original sample of 100 was drawn. Volunteers were accepted only if they were able to read and write. The Ss used in this study were typical of the clinic population which is characterized by little formal education (most Ss did not complete high school) and membership in the lower and lower-middle socioeconomic groups. The average age of the clinic population is about 2 7 years, most Ss being in their twenties. Ss were each given six copies of the PES and asked to rate themselves according to the following instructions. (The symbols in parentheses are used to refer to the instructions in the rest of this account) : "How I am now" (NOW). "How I will be in ten years" (TENYEARS). "How I appear in the eyes of my friends" (FRIENDS). "How I would be if I were what 1 wanted to be, my own ideal" (IDEAL). "How I would be if I were a perfect son (or daughter) to my mother" (MOTHER). "How I would be if I were a perfect son (or daughter) to my father" (FATHER). I n order to eliminate the order effect, each S was asked to complete the ratings in a different order, which was determined by reference to the table of random numbers. The lists of instructions were handed over to the Ss before they started making the ratings. Personal data, such as age, sex, and employment status, were also obtained from the Ss. Statistical calculations were done a t the Computing Centre of the University of Ibadan. In the evaluation of the significance of the difference between the different means, the standard error of the difference between correlated means (snnr) was calculated for each pair of means. The value of SDM was used in computing the z score which was then referred to the table of normal curve functions. The correlation of each item with the other 49 items-that is, item-correlation [(total minus item) ri(~-t,]-was

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computed, and the mean of the r & ( ~ on - ~ all ) 50 items was calculated, thus yielding the average r4( T - 4 , .

Table 1 illustrates characteristics of the different ratings. The fact that the PES consistently yielded a high coefficient alpha on all ratings, coupled with a similar finding in earlier studies by Jegede (4) and Poe ( 6 , 7 ) , clearly demonstrates that the instrument has a high internal consistency reliability which persists under different measurement situations. The high average r4(~-1)obtained in each of the self-ratings is further evidence that, on the whole, the items on the PES hang together a great deal. These findings constitute evidence in support of the construct validity of the PES ( 1, 5). There is one item (namely, item 24) that consistently stands out in that in all six ratings its ri(T-i) was conspicuously low. In fact, it was the lowest on five ratings and next to the lowest on the sixth. On four of the ratings the correlation was negative. On this item, Ss choose between "seeks to please other" and "seeks to please self." The same item behaved in similar fashion in the previous study by Jegede (4). The mean scores of the ratings were compared in order to evaluate the significance of the differences between them. The findings are illustrated in Table 2. Although the mean of the NOW rating was lower than the means of the other ratings, the difference was significant at and above the .05 level only in the case of the IDEAL, FATHER, and MOTHER ratings. The latter two ratings are in fact variants of the IDEAL rating. Hence it is not surprising that the three ratings had the highest means. The large discrepancy between their means and that of the NOW rating suggests that the Ss regarded themselves as inferior to what they would ideally have liked to be. In other words the Ss, as a group, had a low self-concept, a phenomenon that tends to hinder the progress of therapy ( 2 , 3 ) . TABLE

1

CHARACTERISTICS OF R A ~ I N G S Rating

Mean

SD

Alpha

Item correlation

NOW TEN YEARS FRIENDS

347.15 361.74 353.54 388.39 3 74.13 383.87

58.15 76.84 60.58 54.89 60.86 55.33

.94 .98 .96 .96 .96 .96

.so .66 .56 .58 .61 .59

IDEAL MOTHER FATHER

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TABLE 2 COMPARISON OF RATINGS Comparison NOW VS. NOW VS.

TEN YEARS FRIENDS

NOW

IDEAL

VS.

Z

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NOW VS. MOTHER NOW VS. FATHER TEN YEARS VS. IDEAL

Another related issue is the TEN YEARS rating, the mean of which was higher (though not significantly) than the mean of the NOW rating. This suggests that the Ss saw themselves in a better light in future relative to how they regarded themselves a t present. This might be taken as an indication that they expected to function better in future( that is, in 10 years). However, the fact that the mean of the IDEAL rating was so much higher than the mean of TEN YEARS rating (the difference was almost significant a t the .05 level) suggests that the Ss did not expect to achieve their ideal even in 10 years. This phenomenon, along with the low self-concept referred to earlier, may indicate poor prognosis for the Ss as a group. I t would be interesting to relate patients' NOW, TEN YEARS, and IDEAL ratings a t the beginning of therapy to their subsequent course in treatment.

1. ANASTASI,A. Psychological Testing. New York: Macmillan, 1961. FITTS, W. H. The Self-concept and Performance. Nashville, Tenn.: Counselor Recordings & Tests, 1972. 3 . JEGEDE, R. 0. The self-concept of drug addicts. Unpublished manuscript, University of Ibadan, Ibadan, Nigeria, 1975. 4. . Psychometric attributes of the Psychological Effectiveness Scale. J. o f Psychol., 1976, 92, 155-159. J. C. Psychometric Theory. New York: McGraw-Hill, 1967. 5. NUNNALLY, 6. POE, C. A. Internal consistency of a psychological effectiveness scale. Psychol. Rep., 1973, 33, 466. 7. . Development of a psychological effectiveness scale. J. of Psychol., 1973, 85, 81-85. 2.

Box 4187 Ibadan, Nigeria

Further observations on the psychometric properties of the Psychological Effectiveness Scale.

Previous work by Poe and by the present writer have shown that the Psychological Effectiveness Scale (PES) has sufficiently high validity and reliabil...
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