EPP References

EPP used in personal development programme (article)

The EPP and the Selection of Cytoscreeners (article)

The EPP and the Selection of Cytoscreeners

Jeremy N.V. Miles and Alastair G. Gale, Applied Vision Research Unit, Derby University, Mickleover, Derby, DE3.5GX

Background

In the UK, it is recommended that women undergo cervical screening every 3-5 years, from the age at which they become sexually active, to sixty. Screening is carried out via a smear test, which is usually undertaken by a family doctor, or a nurse within the family doctor's clinic. The smear samples cells from the cervix, which are then transferred to a slide. This is then sent to a cytology laboratory for examination.

Cytoscreeners are individuals whose main role is the examination of slides for abnormalities -mainly pre-cancerous and cancerous cells, but also fungal, viral and bacterial infections, and other abnormalities. To examine a single slide may take 1015 minutes, as the slide must be examined over its entire surface, and throughout its depth as cells in the smear sample can overlap one another. A slide may contain as many as 500,000 cells and a screener may be looking for 5-10 abnormal cells amongst those. In addition for a screener to make a decision about a slide they must also consider the medical history of the woman which includes her age, contraceptive use, whether she is pro- or post-menopausal and whether she has had any children.

The standard qualifications required to enter screening are - five O levels or GCSEs are sufficient to be taken on as a trainee screener, selection is then done by interview. Trainees attend a four-week residential training course, and then must train for a minimum of two years in the laboratory. During this time they must complete a logbook of their work and a more experienced worker must re-examine all their work. When they have screened a minimum of 5,000 slides they are eligible to be entered for the Certificate of Competence in Cervical Cytology examination. If they then pass this difficult exam they are eligible to become cytoscreeners, and examine smears on their own.

The training of cytoscreeners is a lengthy and expensive task, and two problems arise. Firstly despite extensive training some screeners never become sufficiently adept to obtain the Certificate of Competence. Secondly they decide not to continue in the profession, either before, or shortly after obtaining the Certificate. Both of these factors place a considerable strain on the resources of a laboratory.

The Project

The co-ordinating body of the NHS Cervical Screening Programme commissioned the Applied Vision Research Unit to carry out research to find a suitable pre-employment test for cytoscreeners, to aid in the selection process. Initial research investigated the aspects of visual skill which were involved in the screening task, and attempted to assess these skills. It became clear, when these studies were unsuccessful, that the visual skill was not the key, the task of screening is not very similar most visual skill measurement tasks. The cells are difficult for the novice to see, but the screeners will be familiar with them. Most visual skill tasks require people to distinguish difficult shapes, with which they are unfamiliar, and require them to do it at speed. In cytological screening the task is much more cognitive, it is not simply the recognition of different shapes, but their interpretation, given the medical history of the woman. In addition, speed is unimportant, but what matters more is the ability to concentrate for long periods of time and maintain vigilance.

It was thought that personality might be a more important factor than visual skill in determining success at screening.

Personality

The particular aspects of personality that were felt to be important were:

Extroversion: Cytological screening is a job that requires long periods of concentration, and provides little stimulation, in addition there is a long history of research that suggests that extroverts perform less well at vigilance tasks than introverts.

Neuroticism: Although the job provides little stimulation, it can be stressful. A mistake, in the form of missing a cancerous, or pre-cancerous smear, can literally be fatal for the woman involved. In addition if high grade cancerous cells are found in subsequent smears, the previous smears which have been taken will be re-examined to see if cancerous signs were present, and the individual who was responsible for screening that smear in the past will be identifiable.

Psychoticism: Neither the financial rewards, nor prospects of promotion are great in screening. It was felt that a person who would make a better screener would have a greater sense of responsibility than non-screeners. In addition both risk-taking and impulsiveness are undesirable characteristics for screeners.

Methodology

The ideal methodology to employ would be a longitudinal one, in which a cohort of screeners would be selected and followed for the first few years of their career. This methodology was rejected because of the length of time it would take before results could be fed back into the screening selection process, and therefore the delay before the economic benefits would be felt. Instead a survey was undertaken of personnel who worked in cytological screening. A random sample of cytology laboratories was taken and sent a questionnaire for each person who worked in the laboratory. This included cytoscreeners, MLSOs and trainee cytoscreeners. The small number oftrainee cytoscreeners was eliminated from the analysis, and, as no significantdifferences emerged between the cytoscreeners and MLSOs (whose main task is also screening) they were combined.

Results

The results displayed here are of a simple comparison of the scores obtained and thescores given In the norm samples provided in the EPP manual, without regard to agegroup and gender. The mean ages were 45.2 (SD 9.5) for cytoscreeners and 42.8 (SD10.1) for MLSOs. The cytoscreeners had been working in screening for a mean of 12.0 years (SD 8.1) and the MLSOs 13.3 years SD (8.6). Considerable differences were found for the three extroversion traits of the EPP. Specifically:

For sociability:

16% (approximately l in 6) of the norm sample score as low as the mean score for cytoscreeners.only 13.9 (approximately 1 in 7) cytology workers score higher than the mean score found in the norm sample. one in twenty (5%) cytology workers score higher than 30, on the sociabilityscale, whereas two out of five (40%) of the norm sample score higher than 30.

For activity:

11% (approximately 1 in 9) of the norm sample score lower than the mean score for cytology workers.only l cytology worker in 10 scores higher than the mean score for the norm sample. the highest score obtained by all 277 respondents on the activity scale was 32, 22% (approximately 1 in 5) of the norm sample scored higher than this.

For assertiveness:

14% (approximately 1 in 7) of the norm sample score lower than the mean score for cytology workers.1 cytology worker in 10 scores higher than the mean score for the norm sample.the highest score obtained by any cytology worker was 28, in the norm sample24% of respondents scored higher than this value.In the neuroticism traits, the differences were less marked:

For anxiety:

60% of people in the norm sample score lower than the mean score for cytology workers

For inferiority:

73% of people in the norm sample score lower than the mean value for cytology workers.

For unhappiness:

The median value for cytology workers is 7, whereas the median for the norm sample is 6.In the three psychoticism traits marked differences again occur:

For risk-taking:

Approximately l in 25 (9 of the sample of 277) cytology workers scored higher than the mean score found in the norm sample for risk-taking.6% of the norm sample scored lower than the median value found for cytology workers on risk-taking.The highest score obtained for all 277 cytology workers was 26. 1 in 5 of the norm sample scored higher than this value.

For impulsiveness:

Approximately 1 in 5 of the cytology workers scored higher than the mean score found in the norm sample1 person in 5 of the norm sample scored less than the median value found in cytology workers.

For irresponsibility:

16.5% (approximately 1 in 6) people working in cytology scored higher than the mean value found in the norm sample.1 person in 3 in the norm sample scored less than the median value found in cytology workers.

These results seem to show some marked differences between individuals who are currently involved in screening and the norm sample.

Conclusions and Implications

The people currently employed in screening seem to be less extrovert and less psychotic than the norm sample. Amongst the neuroticism traits the only difference of any size that was found was inferiority. As a result of this study we will recommend that the EPP be used alongside the existing interview process in the selection of screeners, particularly the extroversion and psychoticism scales. Because the study is only cross sectional we will recommend that the EPP be used in only an advisory fashion, until we have carried out longitudinal research to investigate more thoroughly the ability of the EPP to select appropriate personnel.

Acknowledgement: The initial work in this study was carried out by Dr R Lawson.

This article is copyright of the authors and may not be reproduced elsewhere without the permission of the authors

Other Links

EPP used in personal development programme (article)

The EPP and the Selection of Cytoscreeners (article)

EPP used in personal development programme

Michele Lawty-Jones

Occupational Psychologist
Career Link

The Eysenck Personality Profiler (EPP) has proved to be a valuable tool in our range of psychometric instruments. Whilst we have found the measure to be useful in recruitment. The greatest success was in the area of management development.

We used the measure to promote the idea of life long learning within the workplace. The EPP was given to the management team as the first step of a development programme. Individual one-to-one interviews were then conducted. The EPP was found to be extremely accurate - not a result of the Barnum effect as the EPP does not just provide positive results! The interviews resulted in the development of individual Action Plans involving the recommendation of various training courses including Assertiveness, Motivation and Stress Management. These recommendations were taken forward by the Managing Director.

In addition the Managing Director, with permission from the management team, was given feedback from all the members. A list of key-points was devised to be kept in his top drawer concerning how he was motivated by a pat on the back; how they coped with stress; who required independence within their work etc. The list acted as a reminder of how each individual worked and how to keep that individual motivated and satisfied within their position.

Results were also compared to the results of a Climate Survey conducted at the departmental level. The measurements provide an indication of the effectiveness of the individual management styles as assessed by the EPP. These results fed in to the Action Plans of the individual managers to enable improvement in relations across the company.

Overall the results of the EPP were found to be extremely useful by the companies involved and the individuals tested.

Other Links

EPP used in personal development programme (article)

The EPP and the Selection of Cytoscreeners (article)

EPP Structure

The structure of the Eysenck Personality Profiler

This is a shortened paper from one that appeared in the British Journal of Psychology, 2000, 91, 223-239.

Chris J. Jackson ‡
Adrian Furnham+
Liam Forde*
Tim Cotter*

‡ Department of Psychology
University of Surrey

+Department of Psychology
University College London

*Management Technology Systems
Auckland

Introduction

This study examines the structure and validity of the Eysenck Personality Profiler (EPP). This measure is one of a long line developed by Eysenck: The Maudsley Personality Questionnaire (MPI); the Eysenck Personality Inventory (EPI); the Eysenck Personality Questionnaire (EPQ) and the revised version of the latter (EPQ-R). Each of these measures assess the primary personality traits at the super-factor level - either two (Extraversion and Neuroticism) for the MPI and EPI or three (Extraversion, Neuroticism and Psychoticism) for the EPQ and EPQ-R. The EPP, on the other hand attempts to measure traits at both the primary factor and the super-factor level. It is the only Eysenckian-based instrument which measures traits at the primary factor level, thus yielding 3 superfactor and 21 primary factor scores, as well as a measure of the lie scale, time taken to complete the questionnaire and the total number of Can’t decide responses. Scale names, scale definitions and example items are shown in Table 1.

Table 1

Definitions of the primary scales of the Eysenck Personality Profiler

Superfactor	Primary scale	Description High scorers are:	Example item from each scale
Extraversion	E1: Activity	generally active, energetic, starters of work and proactive.	If you think you may have to wait a few minutes for a lift, are you inclined to take the stairs instead?
	E2: Sociability	inclined to seek out the company of other people and are generally happy and comfortable in social situations.	Is it important to you to be liked by a wide range of people?
	E3:Assertiveness	independent, dominant, and stand up for their rights, perhaps to the extent of being viewed as ‘pushy’.	Do you find it difficult to get rid of a salesperson who is persistent and wasting your time?
	E4: Expressiveness	open with their feelings, volatile and demonstrative.	When you are angry with someone do you wait until you have calmed down before tackling them about the incident?
	E5:Ambition	ambitious, hard-working, competitive, keen to improve their social standing and place a high value on productivity	Do you have a strong desire for self-improvement?
	E6: Dogmatic	uncompromising in their views on most matters and they are likely to defend them vigorously and vociferously.	Would you prefer to fight for your beliefs than let an important issue go unchallenged?
	E7: Aggression	given to the direct or indirect expression of aggression through temper tantrums, fighting, violent argument and sarcasm.	Are you considered an even-tempered person?
Neuroticism	N1: Inferiority	low in self-esteem have a low opinion of themselves and believe themselves to be failures	Do you sometimes feel that you can never do anything right?
	N2: Unhappiness	characteristically pessimistic, gloomy and depressed, disappointed with their existence and at odds with the world.	Do you feel that you often get a raw deal out of life?
	N3: Anxiety	easily upset by things that go wrong and are inclined to worry unnecessarily about unpleasant things that may or may not happen	Is life often a strain for you?
	N4: Dependence	lacking in self-reliance, think of themselves as helpless pawns of fate, are pushed around by other people and events and show a high degree of what has been called ‘authoritarian submission’- the unquestioning obedience to institutional power.	Do you often have the feeling that other people are using you?
	N5: Hypochondria	likely to acquire psychosomatic symptoms and imagine that they are ill.	Do you worry a lot about catching disease?
	N6: Guilt	self-blaming, self-abasing and troubled by their conscience regardless of whether or not their behaviour is really morally reprehensible.	Do you often feel a strong need to confess something that you have done?
	N7: Obsessiveness	careful, conscientious, highly disciplined, staid, finicky and easily irritated by things that are unclean, untidy or out of place.	Is it very important to you that everything should always be neat and tidy?
Psychoticism	P1: Risk-taking	reward seeking and like to live dangerously with little concern for the possible adverse consequences	When you are catching a train, do you often arrive at the last minute?
	P2: Impulsiveness	inclined to act on the spur of the moment, make hurried, often premature decisions and are usually carefree, changeable and unpredictable.	Do you like planning things well ahead of time?
	P3: Irresponsibility	inclined to be overly casual, thoughtless, careless of protocol, unpredictable and socially unreliable	Do you often forget little things that you are supposed to do
	P4: Manipulativeness	detached, calculating, shrewd, worldly, expedient and self-interested in their dealings with other people.	Do you think that honesty is always the best policy?
	P5: Sensation seeking	forever seeking thrills in life and have an insatiable thirst for novel experiences	Do you often long for excitement?
	P6: Tough-mindedness	tolerant of and probably enjoy violence obscenity and swearing.	Do you like scenes of violence and torture in the movies?
	P7: Practical	inclined to be practical, are interested in doing things rather than thinking about them and tend to be impatient with ivory tower theorising.	Are you keen about learning things even though they may have no relevance to your everyday life?
	L: Lie scale	able to put themselves in a positive light so as to try and create a positive impression.	Are you always willing to admit when you have made a mistake?

E1 - E3, N1 - N3 and P1 - P3 together with the Lie scale are used in the EPP-S

The study examines the factor structure of the EPP. The measure has a manual (Eysenck & Wilson, 1991; 1999), evaluative studies (Eysenck, Barrett, Wilson & Jackson, 1992; Costa & McCrae, 1995) and has been used in various studies (e.g. Furnham, Forde & Cotter, 1998ab; Jackson & Wilson, 1994; Wilson & Jackson, 1994).

Recently Eysenck, Wilson & Jackson (1996, 1999) released a shorter version of the Eysenck Personality Profiler. Eysenck, Wilson & Jackson (1997) explain their choice of the nine scales from the original twenty-one: "The present shortened version of the EPP was produced because the original version was found too lengthy for some situations where a quicker turnaround was preferred. Also the large number of traits, while advantageous where detailed and expert consideration was possible, imposed a great load on the person analysing the data, and it was felt that a shorter inventory, containing just 3 scales for each major variable, plus a Lie scale, would give sufficient information for most purposes, particularly if the traits selected were felt to be particularly important for research and applied purposes." (p.9).

The aims of the paper were two fold. First, to provide a replication of the work of Costa & McCrae (1985) using a three times larger sample of data. We attempt a higher order classification of the EPP traits by determining whether a three or five factor solution provides the best description to the 21 primary Eysenckian traits of the EPP and the 9 Eysenckian traits of the EPP-S. We predict that the EPP will be no different from almost all personality questionnaires in that the five factor model will provide the best description of the variance in the dataset. Second, we use confirmatory factor analysis to determine the goodness of fit of prior specified three and five factor solutions with the aim of determining if one solution is better than the other. In line with Costa & McCrae (1985), we predict that the five factor solution will be superior.

Method

Participants

In all, 655 people took part in this study. 54% of the sample were female and the mean age was 32 years (SD= 7.6). Nearly all were native English speaking New Zealanders of European origin. All were employees, or potential employees, of a large communication organization. Most were middle class people who had completed the equivalent of the final school exams (A levels, 12th Grade) and who had been employed for over a decade in a variety of technical and specialist occupations.

Questionnaire

The Eysenck Personality Profiler (EPP; Eysenck & Wilson, 1991) is a 420 item questionnaire measuring 21 primary and 3 super traits. Each item is responded to on a ‘yes’, ‘no’ or ‘can't decide’ scale. The questionnaire is administered by personal computer. In addition to the above scales, there is a dissimulation subscore (similar to the lie-scale on the EPQ), as well as records of how long (in seconds) the subject spends completing the entire test (response latency) and the total number of ‘can't decide’ scores. The EPP has been subjected to various forms of psychometric assessment (Eysenck, Barrett, Wilson & Jackson, 1992; Costa & McCrae, 1995) and studies of specific groups (Jackson & Corr, 1998; Jackson, Furnham & Lawty-Jones, 1999; Jackson & Wilson, 1993; Wilson & Jackson, 1994).

Procedure

Participants were tested as part of a selection and development program in their organization. Over 90% approached completed the task. All were debriefed about their personal results. Since the EPP was administered by computer, each participant was presented with a standard set of instructions to complete the questionnaire. There was no evidence that the subjects set out to create a positive image and recent meta-analysis evidence suggests that the effect of social desirability in personnel selection is minimal (Ones, Viswesvaran, Reiss, 1996).

Results

Means and standard deviations of the scales are reported in Table 2 and are comparable to the means and standard deviations reported by Eysenck et al (1992). One interesting feature is the relatively low means of the Neuroticism scales suggesting that few people admit to neurotic tendencies in the EPP (especially in occupational scenarios). This viewpoint is confirmed by the skewed nature of the frequency plots for these scales and by frequency plots of the items.

Alphas of this study, Eysenck et al (1992) and Costa & McCrae (1995) are also presented in Table 2. Across these studies, there is high consistency in quoted alpha. All three studies show that E4: Expressiveness, E6: Dogmatism and P4: Manipulativeness have alphas less than 0.7. P1: Risk-taking has an alpha <.7 in two out of the three studies and N4: Dependence, N5: Hypochondria, P3: Irresponsible and P6: Tough-mindedness have alphas <.7 in 1 out of the three studies. All the other primary scales have alphas of .7 or greater across all three studies.

Table 2

Descriptive Statistics

(a) Mean SD Alpha1 Alpha2 Alpha3

E1: ACT 27.67 6.70 .71 .76 .83

E2: SOC 20.53 7.34 .78 .81 .84

E3: ASS 22.30 7.30 .74 .75 .76

E4: EXP 16.67 6.13 .58 .60 .50

E5: AMB 24.33 7.34 .77 .80 .82

E6: DOG 13.11 5.53 .58 .58 .56

E7: AGG 11.22 5.81 .64 .70 .69

N1: INF 8.16 7.45 .83 .84 .83

N2: UNH 5.96 6.38 .83 .86 .87

N3: ANX 10.01 7.15 .80 .84 .83

N4: DEP 6.71 5.56 .73 .75 .63

N5: HYP 3.19 4.35 .79 .72 .66

N6: GUI 7.77 6.51 .78 .80 .79

N7: OBS 12.59 6.07 .72 .70 .71

P1: RIS 20.60 6.71 .66 .68 .71

P2: IMP 18.06 7.53 .75 .75 .79

P3: IRR 17.91 6.63 .67 .72 .72

P4: MAN 14.43 6.24 .62 .64 .60

P5: SEN 22.22 7.41 .74 .75 .81

P6: TOU 17.29 7.15 .70 .48 .70

P7: PRA 18.87 7.20 .71 .75 .75

L: LIE 10.34 6.57 .77 - -

Full names of scales are provided in Table 1

Alpha1 = This study, N = 655

Alpha2 = Eysenck, Barrett, Wilson & Jackson (1992) average of male and female alphas, N = 1524

Alpha3= Costa & McCrae (1995), N = 299

We then used promax oblique rotation to perform an exploratory maximum likelihood factor analysis of the data. Promax proceeds in two steps. A varimax solution is first obtained and then it is transformed into an oblique solution in which low loadings are reduced to close to zero values. Promax has advantages over other oblique methods in terms of the general robustness of the solution (Loehlin, 1998). A clear three factor solution is shown in which Extraversion, Neuroticism and Psychoticism superfactors emerge. Factor loadings of >.29, suggest that Extraversion consists of E1: Activity, E2: Sociability, E3: Assertiveness, E4: Expressiveness, E5: Ambition and E6: Dogmatism. Neuroticism consists of N1: Inferiority, N2: Unhappiness, N3: Anxiety, N4: Dependence, N5: Hypochondria, N6: Guilt, N7: Obsessiveness, E6: Dogmatism, and E7: Aggression. Psychoticism consists of P1: Risk-taking, P2: Impulsiveness, P3: Irresponsibility, P4: Manipulativeness, P5: Sensation-seeking, P6: Tough-mindedness, E4: Expressiveness, E7: Aggression and N7: Obsessiveness.

Only E4: Expressiveness, E6: Dogmatism, E7: Aggression and N7: Obsessiveness have factor loadings of >.29 on more than one factor. P7: Practicality does not load on any factor and E7: Aggression loads on Neuroticism and Psychoticism.

A reasonably clear five factor solution is also shown. Using the same criteria, and restricting the names of superfactors to those used by Costa & McCrae (1995), it is possible to attempt an interpretation of the five factor solution. Extraversion consists of five of the seven Extraversion primary scales plus one from Neuroticism and two from Psychoticism (E1: Activity, E2: Sociability, E3: Assertiveness, E5: Ambition, E7: Aggression, N7: Obsessiveness, P3: Irresponsibility, P5: Sensation-seeking, and P7: Practicality). Neuroticism consists of six of the primary factors (N1: Inferiority, N2: Unhappiness, N3: Anxiety, N4: Dependence, N5: Hypochondria, N6: Guilt) plus two from Extraversion (E3: Assertiveness and E6: Dogmatism). Conscientiousness seems a reasonable label for the five scales that loaded on it, of which four were from the Psychoticism group (P1: Risk-taking, P2: Impulsiveness, P3: Irresponsibility, P5: Sensation-seeking) plus E4: Expressiveness and N7: Obsessiveness. Agreeableness also seems a reasonable label for the group of scales that consists of three Extraversion scales (E3: Assertiveness, E6: Dogmatism, E7: Aggressiveness) and P4: Manipulativeness. According to the Big Five nomenclature the fifth factor should be Openness-to-experience. This seems a doubtful label for the scales that loaded on our fifth factor: E3: Expressiveness, P5: Sensation-seeking and P6: Tough-mindedness.

It should be noted that more scales in the five factor solution seem to load on more than one factor. Here E3: Assertiveness, E4: Expressiveness, E6: Dogmatism, E7: Aggressiveness, N7: Obsessiveness, P3: Irresponsibility and P5: Sensation-seeking load on at least two factors with loadings of >.29.

We performed the same promax rotated maximum likelihood factor analysis on the nine scales of the EPP-S. The initial solution of the three factor solution explains 70.9% of the variance and the five factor solution explains 84.3% of the variance. Assuming that factor loadings of >.45 are of importance, the three factor solution shows a clear structure in which Extraversion consists of E1: Activity, E2: Sociability, E3: Assertiveness; Neuroticism consists of N1: Inferiority, N2: Unhappiness, N3: Anxiety; and Psychoticism consists of P1: Risk-taking, P2: Impulsiveness and P3: Irresponsibility. Again assuming that factor loadings >.45 are of importance, the following five factor structure is obtained. Extraversion consists of E1: Activity, E2: Sociability and E3: Assertiveness, Neuroticism consists of N1: Inferiority, N2: Unhappiness and N3: Anxiety, Conscientiousness consists of: P1: Risk-taking and P2: Impulsiveness. P3: Irresponsibility and N2: Unhappiness load separately on one of the two remaining factors which seem unrelated to either Openness-to-experience or Agreeableness.

Next we compared the goodness of fit of the three and five factor solutions of the EPP and EPP-S using various criteria:

Scree slope method

Figure 1 suggests a four factor solution for the EPP and Figure 2 suggests a three factor solution for the EPP-S

2. Number of eigenvalues > 1 (the Kaiser-Guttman rule)

As shown in Figure 1, the EPP has five eigenvalues greater than 1 and, as shown in Figure 2, the EPP-S has three. This rule suggests a five and three factor solution for the EPP and EPP-S respectively

3. Chi-squared test of residuals

As shown in Table 3, the chi-squared test of residuals suggests that more than five factors would provide the optimal solution to the EPP. The chi-squared test suggests a five factor solution to the EPP-S.

4. Difference in chi-squared tests

For both the EPP and the EPP-S, the five factor solution provides a significantly better solution than the three factor solution.

Table 3

Comparison between models

(a) Exploratory models

	Chi 2	df	p

(a) EPP
Chi-squared of 3 factor exploratory model	874.8	150	.00
Chi-squared of 5 factor exploratory model	404.8	115	.00
Difference in c 2 between 3 and 5 factor models	470.0	35	.00
(b) EPP-S
Chi-squared of 3 factor exploratory model	53.9	12	.00
Chi-squared of 4 factor exploratory model	19.8	6	.00
3. Chi-squared of 5 factor exploratory model	2.6	1	.11
4. Difference in chi-squared 2 between 3 and 5 factor models	51.3	11	.00

Figure 1

Scree plot of the EPP

Figure 2

Scree plot of the EPP-S

Discussion

Examination of the alpha coefficients from this study, Eysenck et al (1992) and Costa & McCrae (1995) show that the internal reliability of the EPP scales are generally more than satisfactory. Notable exceptions are E4: Expressiveness, E6: Dogmatism and P4: Manipulativeness. Alphas of E7: Aggressiveness and P1: Risk-taking are also lower than desired.

Our three and five factor solutions provided a replication of Costa & McCrae’s (1985) factor analytic investigation of the EPP (but this time using an N about three times as big). Our exploratory analysis of the EPP found that only some of the standard criteria supported the fit of the five factor model (number of eigenvalues > 1 and difference in chi-squared tests). Costa & McCrae (1995) conclude that a five factor model seems most appropriate for the EPP, but the results of our exploratory data analyses do not strongly support this view.

The factor loading matrices of three and five factor solutions also produce mixed evidence in favour of a five factor model. Whilst it does seem as though five factors resembling Costa & McCrae’s (1995) analysis of the EPP can be extracted, the three factor solution is both more clear and parsimonious. Costa & McCrae (1995) argued that P7: Practicality did not fit a three factor model and was similar to Openness-to-experience. Our analysis also finds that P7: Practicality does not fit a three factor model, but in contrast to Costa & McCrae (1995) now E4: Expressiveness, P5: Sensation-seeking and P6: Tough-mindedness comprise a factor that now has little resemblance to Openness-to-experience.

The initial classification of the EPP primary scales into seven each of Extraversion, Neuroticism and Psychoticism seems generally supported from our analysis except that E6: Dogmatism and E7: Aggression seem as much loaded on other scales as Extraversion and N7: Obsessiveness seems to load on all three scales. As noted previously, P7: Practicality does not fit a three factor solution at all.

The case for a five factor solution with the exploratory analysis seems weaker still with the EPP-S. Only the chi-squared test of the residuals and the difference in Chi-squared tests provide evidence against a three factor solution. The scree slope and the number of eigenvalues >1 methods both suggest a three factor solution. The factor loadings also suggest a three factor solution as it corresponds very closely to that proposed by Eysenck, Wilson & Jackson (1996). In contrast, the five factor model does not produce interpretable factors within the framework of the Big Five.

Confirmatory factor analysis provides best support for a three factor structure of the EPP-S. Aside from the EPP-S, goodness of fit measures are similar for three and five factor solutions. The rule of parsimony might suggest that the three factor solution is superior, but the key observation is really that neither a three nor a five factor solution can be satisfactorily confirmed using standard criteria. We therefore find insufficient evidence in favour of the five factor model and reject our hypothesis.

Eysenck, Wilson & Jackson (1996) have produced a better three factor model with the EPP-S than with the EPP. Eysenck et al (1996) argue that the EPP-S consists of the most important primary scales and in making their choice they seem to have rejected primary scales that are related to Openness-to-experience and Agreeableness. Are these scales important primary scales of personality? Openness-to-experience, for example, seems to be a factor about interest as well as intellect. According to Costa & McCrae (1995), Openness-to-experience is a fundamental higher order personality variable, yet Eysenck, Barrett, Wilson & Jackson (1992) suggest that practicality (its opposite), is of little relevance, especially if the view that Openness-to-experience is a component of Psychoticism is accepted (see Eysenck, 1992). Ferguson & Patterson (1998) concluded that Openness-to-experience was not a ‘pure’ scale of personality as it was also associated with problem solving. McKenzie (1998) also highlights Openness-to-experience as being a major weakness in the five factor model.

Costa & McCrae (1995) conclude their EPP study by stating that their "findings might persuade Eysenckians of the need to move toward the five-factor model" (p. 316). In contrast, our findings do not support the notion that the five-factor model might provide the current optimal description of personality in terms of providing a simple, yet complete, portrait of personality (McAdams, 1992). We believe that the Eysenckian tradition culminating in the EPP still has much to offer psychologists interested in more than a simple description of personality.

The five factor model is primarily based on factor analytical and lexical studies that show most personality datasets conform to a five factor structure. The lexical personality research and factor analytical approach is inductive in the sense that statistical analysis was used to discover structure (Deary & Matthews, 1993). Far less work has been primarily deductive in the sense that personality traits were inferred for theoretical reasons and then scales derived to measure them or that the causes of these dimensions have been explored as a major source of validation for their existence. On the other hand, Eysenck’s three factor model has been based both on factor analytical evidence and other sources such as that derived from what is known of the biological basis of personality (Eysenck, 1967) and may therefore have greater explanatory power (Eysenck, 1997). The concern about whether traits are real or merely heuristic descriptions is a valid question (Briggs, 1989; Tellegen, 1993; Wiggins, 1973).

In summary, our analysis has provided an equivocal answer to the three or five factor debate, and has shown that the Eysenckian classification is as least as psychometrically valid as the Big Five.

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Other Links

EPP used in personal development programme (article)

The EPP and the Selection of Cytoscreeners (article)