Copyright 1992 by the American Psychological Association. Inc. 0022-3514/9243.00

Journal of Personality and Social Psychology 1992, Vol. 62, No. 1,147-153

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Social Desirability and Wiggins's MMPI Content Scales Allen L. Edwards

Lynne K. Edwards

University of Washington

University of Minnesota

Using the Minnesota Multiphasic Personality Inventory (MMPI) item pool, Wiggins (1966) developed 13 scales, each with a homogeneous content. The 13 scales, along with marker scales for the 1st 3 MMPI factors, Edwards's social desirability (SD), Welsh's repression (R), and Wiggins's social desirability (Sd) respectively, were scored in the MMPI. The same scales were scored in an Experimental Multiphasic Personality Inventory (EMPI). A principal-components analysis of the 16 scales when scored in the MMPI resulted in 4 factors. A principal-components analysis of these same scales when scored in the EMPI also resulted in 4 factors. The rotated factor loadings of the scales when scored in the MMPI and when scored in the EMPI were found to be highly congruent. The SD, R, and Sd scales proved to be excellent markers for the 1st 3 factors of the MMPI and also for the 1st 3 factors of the EMPI. Results provide further evidence that the 1st MMPI factor is a social desirability factor rather than a content factor.

of true responses to personality items is a linearly increasing The Experimental Multiphasic Personality Inventory function of the SDSVs of the items,2 it follows that if the propor(EMPI), like the Minnesota Multiphasic Personality Inventory tion of socially desirable responses to each of a large set of (MMPI), contains 550 items and 16 duplicates. Although the personality items is plotted against the SDSVs of the items, the items in the MMPI were selected primarily because the content resulting plot will be V-shaped. That is, items with high SDSVs of the items was believed to have some relevance to psychopawill tend to elicit both a large proportion of true and socially thology, this is not true of the items in the EMPI. desirable responses and that items with low SDSVs will tend to The items in the EMPI were selected from a pool of 2,824 elicit both a large proportion of false and socially desirable normal personality items. Each of these 2,824 items had been responses. rated on a 9-point social desirability scale, ranging from extremely socially undesirable to extremely socially desirable by a If a set of items is selected from one or both of the two extremes of the social desirability continuum, and if these items group of college students; for this sample, the average rating, or social desirability scale value (SDSV), was known. An indepen- are keyed for socially desirable responses, then, in general, the socially desirable response will also be the modal response. A dent group of college students had described themselves by set of items keyed for both SD and modal responses is defined answering each of the 2,824 items true or false, and for this as an SD scale. Scores on SD scales are regarded as measuring sample, the proportion of individuals answering each of the individual differences in the tendency to give socially desirable items true, P(T), was known. responses to personality items, under the standard conditions Similar item statistics are available for the 550 items in the in which personality scales and inventories are ordinarily adMMPI. Messick and Jackson (1961) published the SDSVs of the ministered. Note that the definition of an SD scale in no way MMPI items based on the ratings of a group of college students. specifies that the items selected have a homogeneous content. Using an independent group of college students, Goldberg and The items in SD scales are not selected on the basis of their Rorer (1963) published the P(T)s for each of the MMPI items. content, but rather on the basis of the rated social desirability of For each of the 550 items in the MMPI, a corresponding item the content. was selected from the pool of 2,824 items in such a way to The first social desirability scale constructed consisted of 39 match closely as possible the SDSV and the P(T) of the MMPI items from the MMPI. It was constructed in the early days of item. The 550 items thus selected form the EMPI. In selecting research on the social desirability variable and before what is items for the EMPI, no attempt was made to match the content now known about social desirability. It is simply fortuitous that of the MMPI items. Indeed, this would have been an impossiall but one of the items in Edwards's 39-item MMPI SD scale ble task because the 2,824 items from which the EMPI items (Edwards, 1957) satisfy the aforementioned criteria for an SD were selected are normal personality items, whereas the MMPI scale. items are primarily relevant to some aspect of psychopathology. Although personality researchers seem to be aware that the A socially desirable response to a personality item has been P(T)s of personality items are a linearly increasing function of defined as a true response if the item has an SDSV greater than the SDSVs of the items, they do not seem to be aware that this 5.0 or as a false response if the item has an SDSV less than 5.0.' function is different for high and low scorers on the SD scale. Because it has now beenfirmlyestablished that the proportion 1 A socially undesirable response is, of course, just the reverse of a socially desirable response. 2 For a review of the evidence, see Edwards (1970).

Correspondence concerning this article should be addressed to Allen L. Edwards, Department of Psychology, NI-25, University of Washington, Seattle, Washington 98195. 147

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ALLEN L. EDWARDS AND LYNNE K. EDWARDS

Suppose, for example, that the SD scale and another independent set of personality items, with a wide range of SDSVs, are administered to a large sample of individuals. The sample is then divided into a group with high scores on the SD scale (the HSD group) and a group with low scores on the SD scale (the LSD group). The regression line of P(T) on SDSV for the set of independent personality items can then be obtained for each group. These two regression lines will have different slopes, with the slope for the HSD group being steeper than the slope for the LSD group. In general, the intersection of the two regression lines has been found to be at approximately 5.8 on the social desirability continuum. For items falling to the right of 5.8 on the social desirability continuum, the expected value of a true and socially desirable response is greater for the HSD group than for the LSD group. For items falling to the left of 5.8 on the social desirability continuum, the expected value of a false and socially desirable response is also greater for the HSD group than for the LSD group. In other words, those items with either high SDSVs or low SDSVs are the items most sensitive to individual differences in the tendency to give socially desirable responses to personality items. The difference in the regression lines of P(T) on SDSV for HSD and LSD groups was first reported by Edwards and Walker (1962) and subsequently replicated with different sets of personality items by Edwards and Diers (1963) and by Edwards, Gocka, and Holloway (1964). These three studies strongly suggest (a) that scores on the SD scale are measuring a general personality trait (i.e., individual differences in the tendency to give socially desirable responses to personality items in self-description under the standard conditions in which personality scales and inventories are ordinarily administered) and (b) that this trait is not dependent on the specific content of the items. Items with high SDSVs, regardless of content, are more likely to be answered true by individuals with high rates of socially desirable responding than by individuals with low rates ofsocially desirable responding. Similarly, items with low SDSVs, regardless of content, are more likely to be answered false by individuals with high rates of socially desirable responding than by individuals with low rates of socially desirable responding. In the present study, we compared a set of 13 MMPI scales, each with a homogeneous item content, with a corresponding set of 13 EMPI scales, each with a heterogeneous item content. Although the 13 MMPI scales and the corresponding 13 EMPI scales do not have item content in common, they do have certain structural properties in common. For each of the MMPI scales, there is a corresponding EMPI scale such that both scales have the same number of items. Each of the items in the EMPI scale has an SDSV and a P(T) that match as closely as possible each of the corresponding items in the MMPI scale. It follows that if the trait-keyed response to an item in the MMPI scale is also a socially desirable response, then the corresponding item in the EMPI scale will also be keyed for a socially desirable response, and that both scales will have the same proportion of items keyed for socially desirable responses.3 Furthermore, because the SDSVs of the items in the MMPI scale and the corresponding EMPI scale are closely matched, both scales will have approximately the same social desirability intensity index (Edwards & Walsh, 1963).

Method The 13 MMPI scales used in the present study are Wiggins's (1966) content scales. Starting with the original item-content classification of the MMPI items by Hathaway and McKinley (1940), Wiggins developed a new set of 13 MMPI scales. Because the items in each of the 13 scales developed by Wiggins have a relatively homogeneous content, the scales have become commonly known as the MMPI content scales. The MMPI records for a sample of 572 male and 270 female college students were scored on the 13 content scales. No large differences were observed between the means of the male and female samples, and the results reported are based on the combined sample of 842 students. It may be noted that Wiggins developed his content scales using a combined sample of men and women. The scoring keys for the 13 content scales were then applied to a sample of 310 male and 307 female college students who had been administered the EMPI. Again, the results reported are based on the combined sample of 617 students. In addition to the 13 content scales, we included in our analysis marker scales for the first three MMPI factors. The SD scale, as described previously, consists of 39 items all of which are keyed for socially desirable responses. The SD scale has proven to be an excellent marker scale for the first MMPI factor in every principal-components analysis of MMPI scales in which it has been included. The R (repression) scale was developed by Welsh (1956) to measure the second MMPI factor. The R scale consists of 40 items, all of which are keyed false. The SDSVs of the items are—for the most part—uniformly distributed over the social desirability continuum, and because all of the items are keyed for false responses, the R scale has a degree of balance in the number of items keyed for socially desirable and socially undesirable responses. The correlation between scores on the R scale and the SD scale is low, and the R scale has consistently been found to have a high loading on the second MMPI principal-components factor. The Sd (social desirability) scale consists of 40 items and was developed by Wiggins (1959). The items in the Sd scale are those that were found to differentiate between individuals taking the MMPI under standard instructions and those taking the MMPI under instructions to fake good. The Sd scale has been found to have a low loading on both the first and the second MMPI factors and ordinarily has its highest loading on the third or sometimes the fourth MMPI principal components. The Sd scale was included in our study as a potential marker scale for the third MMPI factor. A principal-components analysis of the 16 scales, as scored in the MMPI, resulted in four factors with eigenvalues of 5.986,2.164,1.696, and 1.042, respectively. These four factors were rotated using a varimax rotation. A principal-components analysis of the 16 scales, as scored in the EMPI, also resulted in four factors with eigenvalues of 6.264, 2.274, 1.387, and 1.119, respectively. These four factors were also rotated using a varimax rotation.

Results Table 1 shows the means and standard deviations for the 16 scales when scored in the MMPI and in the EMPI. There are no large differences in the means of the scales when they are scored in the MMPI and when they are scored in the EMPI, and the means for the three marker scales—R, Sd, and SD—

3

It follows that both scales will also have the same proportion of items keyed for socially undesirable responses.

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SOCIAL DESIRABILITY AND MMPI CONTENT SCALES Table 1

Means and Standard Deviations of the Content and Marker Scales When Scored in the MMPI and When Scored in the EMPI EMPI

MMPI

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Scale 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16.

Social maladjustment Depression Feminine interests Poor morale Religious fundamentalism Authority conflict Psychoticism Organic symptoms Family problems Manifest hostility Phobias Hypomania Poor health R Sd SD

M

SD

M

SD

No. of items in scale

9.2 7.4 12.9 7.8 5.4 7.9 7.6 5.5 4.7 8.7 5.9 13.4 4.6 15.7 13.7 30.5

5.8 5.0 5.7 5.0 3.2 3.8 4.8 3.6 2.9 4.3 3.6 3.8 3.2 4.3 4.2 5.5

9.4 8.6 14.4 8.8 6.3 8.1 9.3 6.5 4.7 9.9 7.7 13.3 7.8 15.7 14.2 29.4

3.4 3.8 3.5 3.6 1.7 2.9 4.7 3.4 2.3 3.6 3.3 2.6 2.9 3.7 3.5 4.9

27 33 30 23 12 20 48 36 16 27 27 25 28 40 40 39

Note. MMPI = Minnesota Multiphasic Personality Inventory; EMPI = Experimental Multiphasic Personality Inventory; R = Welsh's (1956) repression; Sd= Wiggins's (1959) social desirability; SD = Edwards's (1957) social desirability.

when scored in the MMPI are closely equivalent to the means of these same scales when they are scored in the EMPI. Column 2 of Table 2 shows the correlations of the scales when scored in the MMPI with the MMPI SD scale.4 The correlations of these same scales when scored in the EMPI with the EMPI SD scale are shown in column 3. Note that the intercorrelations of the three marker scales are much the same, regardless of whether they are scored in the MMPI or the EMPI. For example, the correlation coefficient between R and SD when scored in the MMPI is .06, and this is also the correlation coefficient between these two scales when they are scored in the EMPI. When scored in the MMPI, the correlation coefficient between R and Sd is - . 2 7 , and when scored in the EMPI, the correlation coefficient between the same two scales is —.29. With respect to the correlation coefficient between SD and Sd, the correlation is .15 when the scales are scored in the MMPI and .02 when the scales are scored in the EMPI. The correlation coefficient between the two sets of correlations shown in column 2 and column 3 is equal to .92. Thus, essentially the same pattern of correlation coefficients of the scales with the SD scale is obtained, regardless of whether the scales are scored in the MMPI or in the EMPI. Column 4 shows the correlations of the scales with the MMPI R scale when scored in the MMPI, and column 5 shows the correlation coefficients of these same scales with the EMPI R scale when they are scored in the EMPI. Again, there is a substantial relationship between the two sets of correlation coefficients. The correlation between the two sets of correlation coefficients shown in column 4 and column 5 is .85. Column 6 shows the correlations of the scales when they are scored in the MMPI with the MMPI Sd scale, and column 7 shows the correlation coefficients of the same scales when they

are scored in the EMPI with the EMPI Sd scale. The correlation coefficient between the correlation coefficients shown in column 6 and column 7 is equal to .74. Table 3 shows the varimax rotated factor loadings of the scales when they are scored in the MMPI and when they are scored in the EMPI. Note that the MMPI SD scale is an excellent marker scale for the first MMPI factor and that the EMPI SD scale is an excellent marker scale for the first EMPI factor. Similarly, the R scale serves as a marker scale for the second MMPI factor, and this same scale when scored in the EMPI also serves as a marker scale for the second EMPI factor. The Sd scale has a high loading on the third MMPI factor, and the same scale when scored in the EMPI also has a high loading on the third EMPI factor. The correlation coefficient between the MMPI first factor loadings and the EMPI first factor loadings is equal to .93 and Tucker's coefficient of congruence 5 between the two sets of factor loadings is equal to .96, indicating that the two sets of factor loadings are highly congruent (Harman, 1976, p. 344). The correlation coefficient between the MMPI second factor loadings and the EMPI second factor loadings is equal to .85, and for these two factors, Tucker's coefficient of congruence is equal to .86. For the third MMPI and EMPI factors, the correlation coefficient between the two sets of factor loadings is .91, and Tucker's coefficient of congruence is equal to .89. With

4

All correlation coefficients reported in this article are Pearson product-moment correlation coefficients. 5 Ten Berge (1986) has listed a number of attractive properties of the coefficient of congruence as a measure of agreement between two vectors of factor loadings.

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ALLEN L. EDWARDS AND LYNNE K. EDWARDS Table 2 Correlations of the Scales With Three Marker Scales When Scored in the MMPI and When Scored in the EMPI R

SD

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Scale 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16.

Social maladjustment Depression Feminine interests Poor morale Religious fundamentalism Authority conflict Psychoticism Organic symptoms Family problems Manifest hostility Phobias Hypomania Poor health R Sd SD

Sd

MMPI

EMPI

MMPI

EMPI

MMPI

EMPI

-.54 -.83 -.11 -.83 -.04 -.38 -.64 -.61 -.44 -.54 -.55 -.50 -.56 .06 .15 —

-.66 -.73 -.16 -.66 .06 -.50 -.74 -.63 -.63 -.52 -.67 -.26 -.60 .06 .02 —

.35 -.11 .10 -.11 -.04 -.38 -.24 -.06 -.17 -.49 .05 -.47 -.01 — -.27 .06

.08 -.07 .08 -.14 -.13 -.33 -.22 .23 -.12 -.38 .14 -.41 .11 — -.29 .06

-.31 -.17 -.04 -.14 .47 -.05 .01 -.13 -.19 -.03 -.05 .09 -.14 -.27 — .15

-.15 .04 -.09 -.08 .33 .17 .29 -.01 -.03 .19 -.07 .22 -.13 -.29 — .02

Note. MMPI = Minnesota Multiphasic Personality Inventory; EMPI = Experimental Multiphasic Personality Inventory; R = Welsh's (1956) repression; Sd = Wiggins's (1959) social desirability; SD = Edwards's (1957) social desirability.

In Table 4, we have classified the scales according to the factor on which they have their highest absolute loading. Note that Factor I is not only well defined for both the MMPI and the EMPI, but it is also similarly defined with the same nine scales having their highest absolute loading on both the EMPI first factor and the MMPI first factor. Factor II is also well defined with the same four scales having their highest absolute loading

respect to the MMPI and EMPI fourth factor loadings, the correlation coefficient between the two sets of loadings is equal to .82, and Tucker's coefficient of congruence is equal to .83. Thus, one sees that the factor structure of the 13 content and 3 marker scales when they are scored in the MMPI is quite comparable to the factor structure of these same scales when they are scored in the EMPI.

Table 3 Varimax Rotated Factor Loadings of the Content and Marker Scales When Scored in the MMPI and When Scored in the EMPI EMPI

MMPI Scale 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16.

Social maladjustment Depression Feminine interests Poor morale Religious fundamentalism Authority conflict Psychoticism Organic symptoms Family problems Manifest hostility Phobias Hypomania Poor health R Sd SD

I

II

III

IV

I

II

III

IV

.63 .87 .17 .88 .13 .34 .68 .68 .42 .52 .66 .48 .63 .05 -.18 -.93

-.48 .17 -.06 .11 -.08 .54 .41 .18 .34 .61 -.05 .65 .09 -.86 .26 -.10

-.16 -.06 .04 .02 .84 -.17 -.01 -.09 -.38 -.07 .11 .04 -.09 -.14 .81 .05

-.21 -.03 .88 -.04 .14 -.44 .08 .11 .19 -.29 .37 .08 .11 .07 -.01 .05

.74 .82 .10 .57 -.08 .52 .78 .81 .66 .51 .80 .12 .72 .14 -.01 -.88

.10 .23 -.03 .43 .08 .52 .32 -.22 .30 .58 -.09 .73 -.06 -.82 .20 -.22

-.24 .01 .05 -.13 .76 .06 .29 .04 -.07 .10 .04 .14 -.11 -.14 .81 .05

.01 -.07 .87 .42 .28 -.34 -.08 -.02 .16 -.22 .22 .27 .03 .12 -.23 -.11

Note. MMPI = Minnesota Multiphasic Personality Inventory; EMPI = Experimental Multiphasic Personality Inventory; R = Welsh's (1956) repression; Sd = Wiggins's (1959) social desirability; SD = Edwards's (1957) social desirability.

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tial loadings on the first MMPI factor (e.g., Poor Morale, Psychoticism, and Organic Symptoms). Why should an individual who scores high on Depression also tend to have high scores on the various other scales that have substantial positive loadings on the first MMPI factor? Why should Organic Symptoms be associated with Phobias? It appears to be obvious that high scores on thefirstMMPI factor are associated with a variety of different aspects of what might be called psychopathology. However, interpretation of the first MMPI factor as measuring psychopathology surely does not apply to the first factor of the EMPI. The same scales that load the first MMPI factor also load the first EMPI factor, yet the items in the content scales as scored in the EMPI have neither a homogeneity of content nor a content that is similar to the item content of the scales as scored in the MMPI. It is highly improbable that any clinical psychologist, no matDiscussion ter how skilled or how familiar with the MMPI, could sort the EMPI items into the 13 content categories that Wiggins (1966) The results we have reported with respect to the first factor describes. For example, could a skilled clinician select from the loadings of Wiggins's 13 MMPI content scales when they are 550 EMPI items the 27 items that are scored in the Social Malscored in the MMPI and in the EMPI are relevant to the controadjustment scale, the 33 items that are scored in the Depression versy regarding the interpretation of the first factor of the scale, and so on? The labels assigned to the 13 content scales MMPI as a Content factor or as a Social Desirability factor. An when they are scored in the MMPI simply do not apply when examination of the MMPI items in each of the scales with these same scales are scored in the EMPI. substantial loadings on thefirstMMPI factor leaves little doubt that the scale names do indeed summarize the item content. To document this point, we selected the first six items keyed That is, the 33 MMPI items in the Depression scale are relevant for true responses in 1 of the 13 content scales. The content and to what is generally referred to as depression. The same is true of item numbers of these six items, as scored in the EMPI, are as the MMPI items in the other scales that have their highest follows: loading on the first MMPI factor. However, the first MMPI 10. I am not dependable in an emergency. factor does not measure simply depression. Various other scales with a different homogeneity of item content also have substan14. I get upset if someone prevents me from having my own way.

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on both the EMPI second factor and the MMPI second factor. With respect to Factor III, the same two scales have their highest absolute loading on both the MMPI third factor and the EMPI third factor. Factor IV in both the MMPI and the EMPI is a singleton with only one scale, Feminine Interests, having its highest loading on both the MMPI and the EMPI fourth factor. This is not unexpected. As Table 2 shows, the Feminine Interests scale has relatively low correlations with the SD, R, and Sd scales in both the MMPI and the EMPI and, consequently, has little variance in common with these scales. Thus, it is reasonable that Feminine Interests has low loadings on the first three EMPI and MMPI factors on which SD, R, and Sd (respectively) have their highest loadings.

29. I often forget about an appointment I have made. Table 4 Classification of the Content and Marker Scales According to the Factor on Which They Have the Highest Absolute Loading Factor Factor I 1. Social maladjustment 2. Depression 4. Poor morale 7. Psychoticism 8. Organic symptoms 9. Family problems 11. Phobias 13. Poor health 16. SD Factor II 6. Authority conflict 10. Manifest hostility 12. Hypomania 14. R Factor III 5. Religious fundamentalism 15. Sd Factor IV 3. Feminine interests

MMPI

EMPI

.65 .87 .88 .68 .68 .42 .66 .63 -.93

.74 .82 .57 .78 .81 .66 .80 .72

.54 .61 .65 -.86

.52 .58 .73 -.82

.84 .81

.76 .81

.88

.87

Note. MMPI = Minnesota Multiphasic Personality Inventory; EMPI = Experimental Multiphasic Personality Inventory; SD = Edwards's (1957) social desirability; R = Welsh's (1956) repression; Sd= Wiggins's (1959) social desirability.

34. I get angry if I feel my opinions are being attacked. 72. I tend to get so concerned about the details of a problem that the problem itself never gets solved. 125. I am not aware that I have any undesirable traits. We challenge the reader to determine to which of the 13 MMPI content scales these EMPI items belong. The answer is given in a footnote.6 We regard scores on SD scales as measuring a normal and general personality trait (i.e., individual differences in the tendency to give socially desirable responses in self-description under the standard conditions in which personality inventories and scales are ordinarily administered). Individuals with high scores on an SD scale tend to give socially desirable responses not only to items relevant to psychopathology, but also to personality items in general, provided these items have relatively low or relatively high SDSVs.

6 The 6 EMPI items listed correspond to the first 6 items keyed for true responses in the Poor Health scale of the MMPI. In abbreviated form, the MMPI items are (a) having a lump in the throat, (b) having diarrhea once a month or more, (c) having acid stomach, (d) having a cough most of the time, (e) having discomfort in pit of stomach, and (f) having a great deal of stomach problems.

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Recall, for example, that the regression lines of P(T) on SDSV for HSD and LSD subjects have different slopes, with the slope for HSD subjects being steeper than the slope for LSD subjects. Because the point of intersection of the two regression lines is at approximately 5.8 on the social desirability continuum, the two regression lines are farthest apart at the two extremes of the social desirability continuum. Now, if an MMPI scale contains a substantial number of items with SDSVs falling at one or both extremes of the social desirability continuum, and if these items tend—in general—to be keyed for trait and SD responses, then HSD subjects can be expected to give more trait and SD responses to these items than LSD subjects. Consequently, scores on this MMPI scale can be expected to be positively correlated with scores on the SD scale. In addition, because the SDSVs of the items in the corresponding EMPI scale are approximately the same as those of the items in the MMPI scale, one can also expect scores on the EMPI scale to be positively correlated with the SD scale. Similarly, if the items in the MMPI scale tend—in general—to be keyed for trait and socially undesirable responses, then HSD subjects can be expected to give fewer trait and socially undesirable responses to these items than LSD subjects. In this instance, one can expect scores on the MMPI scale to be negatively correlated with scores on the SD scale.7 Similar considerations apply to the corresponding EMPI scale. For example, HSD subjects are more likely to respond false to an item in an MMPI scale measuring psychopathology, which has an SDSV of 1.5 and is keyed for a true response, than are LSD subjects. The HSD subjects, however, are also more likely to respond false to the corresponding item in the EMPI, which also has an SDSV of 1.5, regardless of the specific content of the item in the EMPI. In other words, it is not so much the content of an item, but rather the SDSV of the item that is of importance. In summary, although an MMPI scale and its EMPI counterpart do not have a common content, the two scales do have in common certain structural properties. For example, the P(T)s and the SDSVs of the items in a given MMPI scale are closely matched by the P(T)s and SDSVs of the corresponding items in the EMPI scale. Consequently, if the trait-keyed response to an item in the MMPI scale is also a socially desirable response, then the corresponding item in the EMPI scale will also be keyed for a socially desirable response. Thus, both scales will have the same number of items keyed for socially desirable responses. Similarly, if the trait-keyed response for an item in a given MMPI scale is also an SUD response, then the corresponding item in the EMPI scale will also be keyed for a socially desirable response. Thus, both scales will have the same number of items keyed for socially desirable and socially undesirable responses. In addition, because corresponding items in both the MMPI and the EMPI scales have approximately the same SDSVs, both scales will have approximately the same social desirability intensity index.8 It is obvious that the common structural properties of an MMPI scale and its EMPI counterpart, as described, are not dependent on the two scales having the same item content. Given (a) that there are reliable individual differences in rates

of social desirability responding, as measured by the SD scale; (b) that this individual difference variable is operative with respect to both the items in the MMPI and the items in the EMPI; and (c) that an MMPI scale and its EMPI counterpart have the common structural properties cited, then it follows that the correlation of the scale when scored in the MMPI with the MMPI SD scale should be related to the correlation of that same scale when scored in the EMPI with the EMPI SD scale. Similarly, the first factor loading of the scale when scored in the MMPI should be related to the first factor loading of that same scale when scored in the EMPI. The results obtained in this study with respect to the first factor loadings of MMPI scales when scored in the MMPI and when scored in the EMPI are consistent with the results obtained in other studies,9 comparing the MMPI and the EMPI (Edwards, 1966; Edwards & Clark, 1987). The large number of MMPI scales involved in these studies provide strong support for the interpretation of the first MMPI factor as measuring individual differences in the tendency to give socially desirable responses in self-description. 7

It should be obvious that the conditions under which an MMPI scale can be expected to have either a positive or a negative correlation with the SD scale are not limited to MMPI scales. They are equally applicable to personality scales in general. 8 See Edwards and Edwards (1991) for a detailed discussion of the social desirability intensity index. 9 The MMPI scales involved in these studies were for the most part empirically derived scales and, consequently, unlike the Wiggins's (1966) content scales used in the present study, did not necessarily have a homogeneity of content.

References Edwards, A. L. (1957). The social desirability variable in personality assessment and research. New York: Dryden Press. Edwards, A. L. (1966). A comparison of 57 MMPI scales and 57 experimental scales matched with the MMPI scales in terms of item social desirability scale values and probabilities of endorsement. Educational and Psychological Measurement, 26,15-27. Edwards, A. L. (1970). The measurement ofpersonality traits by scales and inventories. New York: Holt, Rinehart & Winston. Edwards, A. L., & Diers, C. J. (1963). Neutral items as a measure of acquiescence. Educational and Psychological Measurement, 23, 687-698. Edwards, A. L., Gocka, E. E, & Holloway, H. (1964). The development of an MMPI acquiescence scale. Journal ofClinical Psychology, 20, 148-150. Edwards, A. L., & Walker, J. N. (1962). Relationship between probability of item endorsement and social desirability scale value for high and low groups on Edwards' SD scale. Journal of Abnormal and Social Psychology, 64, 458-460. Edwards, A. L., & Walsh, J. A. (1963). The relationship between the intensity of the social desirability keying of a scale and the correlation of the scale with Edwards' SD scale and the first factor loading of the scale. Journal ofClinical Psychology, 19, 200-203. Edwards, L. K,&Clark, C. L. (1987). A comparison of Jtaefirstfactor of the MMPI and the first factor of the EMPI: The PSD factor.

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Social desirability and Wiggin's MMPI content scales.

Using the Minnesota Multiphasic Personality Inventory (MMPI) item pool, Wiggins (1966) developed 13 scales, each with a homogeneous content. The 13 sc...
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