3.1 Reliability
In the reliability exercise, the test-retest reliability technique was used.
According to this method the same instrument is applied to the same respondents
at a later stage and the correlation between the two scores is then calculated
(Huysamen 1980:54; Mulder 1981:211).
The questionnaire was administered by the respective people participating
in the exercise. All of these participants are trained in Discus and
how to administer the instrument. The instrument was administered for
the first exercise to obtain a pretest score. The exercise was then
repeated with the same respondents after a period of three months in
order to obtain a post-test score.
A statistical evaluation of the raw data, resulting from the exercise,
was then obtained by using the SAS system, reflecting Pearson's Product-moment
correlation coefficient (coefficiency of stability).
3.1.1 The Questionnaire
The questionnaire consists of 24 questions each of which
presents the respondents with four options. The respondents'
task is to select one of the options that most closely resembles
themselves, and one that least closely describes them. The
respondents are required to focus on the role they fulfil in
their work environment and answer all the questions in relation
to that role.
- Phrase-based
The phrase-based question set contains questions of the form 'Behaving compassionately
towards others' or 'Persuading others to your point of view'.
- Adjective-based
The adjective-based question set contains words such as 'kind-hearted', 'persuasive'
and 'modest'.
For the purpose of this exercise the phrase-based questionnaire was
used because it is easier to understand.
3.1.2 Sampling Technique and Size
Various companies were approached to assist with the exercise
as reflected in table 1.
| TABLE
1: COMPANIES USED |
Technikon Natal
Edgars Group (Gauteng)
Toyota South Africa (KZN)
NBS
BB Cereal |
The questionnaire was administered to 90 respondents. These respondents
were randomly selected from the respective companies reflected in table
1. A statistical evaluation of the raw data resulting from the testing
was then obtained by using the SAS system reflecting Pearson's product-moment
correlation coefficient.
3.1.3 Results
The correlation analyses are reflected in table 2.
TABLE
2: CORRELATION MATRIX: BEFORE AND AFTER SCORES
Pearson's Product-Moment Correlation Coefficient
r = values
p = values |
| |
DOMINANCE
BEFORE |
INFLUENCE
BEFORE |
STEADINESS
BEFORE |
COMPLIANCE
BEFORE |
DOMINANCE
AFTER |
r=0.72831
p=0.0001 |
r=0.11048
p=0.2972 |
r=0.61917
p=0.0001 |
r=0.16192
p=0.1252 |
INFLUENCE
AFTER |
r=0.22558
p=0.0325 |
r=0.64578
p=0.0001 |
r=0.5282
p=0.6210 |
r=0.33619
p=0.0012 |
STEADINESS
AFTER |
r=0.58452
p=0.0001 |
r=0.14199
p=0.1819 |
r=0.73004
p=0.0001 |
r=0.22517
p=0.0329 |
COMPLIANCE
AFTER |
r=0.17989
p=0.0898 |
r=0.36256
p=0.0004 |
r=0.17270
p=0.1036 |
r=0.55000
p=0.0001 |
The significance level chosen for this instrument is alpha = 5%. Where
the p-value is less than 0.05, the scores show a significant correlation.
In the reliability analysis the p-value in all the cases is as low as
0.0001. This indicates significance at alpha = 0.001. It can therefore
be said the correlation is significant at 1% level.
The reliability coefficient of the measuring instrument is close to
1 and can therefore be seen as reliable.
3.2 Validity
3.2.1 Content Validity
Content validity of the instrument is determined when the
instrument is designed. Content validity refers to the extent
in which the instrument measures what it is supposed to measure
(De Wet, De K Monteith, Steyn & Venter 1981:146; Huysamen
1980:95; Mulder 1989:219).
Each question in the Discus instrument was evaluated by the designers
of the instrument, namely Axiom. Although content validity was done
by Axiom, the researcher also decided to measure validity in terms of
criterion-related validity.
3.2.2 Criterion-related Validity
By applying the method of criterion-related validity, an
exploratory study was done by correlating all 15 Factors in
Cattell's 16-PF with the four dimensions in the Discus. Factor
B was not considered as doubts exist in the literature as to
the validity of Factor B (intelligence) within a personality
test.
Criterion-related validity was restricted to validation procedures
in which the test scores of a group of respondents are compared with
ratings of other measurements (Aiken 1994:96).
Nunally (1978) claims that it is unrealistic to expect exceptionally
high correlation coefficients and Anastasi (1976) says that coefficients
of 0.20 and higher can be significant.
3.2.3 Sampling Size and Technique
In this exercise employees of the Edgars group, Toyota
South Africa and Technikon Natal were used. It was therefore
decided to use the Discus and Cattell's 16-PF (Form A) for
this exercise.
In an attempt to determine a correlation between the Discus dimensions
and Cattell's 16-PF, scores on the 16-PF were obtained from 120 employees
employed by the abovementioned companies. These respondents were randomly
selected from line managers, middle managers, professionals and junior
officials. The sample was drawn from all organisational functions and
cultural groups within the organisations.
3.2.4 Measuring Instruments
3.2.4.1 The Discus Questionnaire
This questionnaire has already been discussed in paragraph 3.1.1.
3.2.4.2 Cattell's 16-PF
The 16-PF is specifically constructed for the purpose of determining individual
attitudes, perceptions and personality characteristics. It was developed
by R.B. Cattell and published in 1949. The A and B Forms of the test consist
of 187 items each and are suitable for adults with at least standard 10 or
equivalent education. The 16-PF can be used for the evaluation of personality
in people of different population groups because it is culture friendly (Prinsloo
1992:21-22).
Cattell applied the technique of factor analysis and obtained a set
of 16 primary factors. The rationale behind the 16-PF is that a questionnaire
which is based on revealed traits, obtained through mathematical techniques
from a large pool of possible personality descriptions, is capable of
measuring reliably and validly the true constructs present in humans.
The general purpose of the 16-PF is to describe testees' personality
and predict behaviour using a set of selected, structured items. The
test has many practical applications, some of which are mentioned below:
- Career counselling
- Fruitful employment in industrial and career settings
- Counselling
- Clinical settings
- Extremely useful research
The results of a factor analysis completed by Cattell identified the following
16 factors (table 3).
| TABLE
3: THE HIGH AND LOW FACTORS OF THE 16-PF |
|
LOW SCORES
|
FACTOR
1 2 3 4 5 6 7 8 9 10
|
HIGH SCORES
|
|
Reserved
|
A |
Outgoing
|
|
Dull
|
B |
Bright
|
|
Easily Upset
|
C |
Calm
|
|
Submissive
|
E |
Dominant
|
|
Serious
|
F |
Impulsive
|
|
Frivolous
|
G |
Responsible
|
|
Shy
|
H |
Bold
|
|
Tough-minded
|
I |
Tender-minded
|
|
Trusting
|
L |
Suspecting
|
|
Practical
|
M |
Fanciful
|
|
Forthright
|
N |
Calculating
|
|
Secure
|
O |
Apprehensive
|
|
Conservative
|
Q1 |
Liberal
|
|
Group-dependent
|
Q2 |
Self-sufficient
|
|
Uncontrolled
|
Q3 |
Controlled
|
|
Relaxed
|
Q4 |
Tense
|
For interpretation purposes, factor scores of 1 to 3 and 8 to 10 are
considered. The low numbers of each factor are pictured as portraying
one extreme of the profile and the high numbers as portraying the other.
It should be pointed out that Cattell, in analysing all 16 factors,
came up with clusters of several adjectival descriptors for each factor.
Table 3 depicts words representative of factor clusters. The Kuder-Richardson
8-method was used to determine the reliability of the 16-PF. Table 4
reflects the reliability figure for each factor.
|
TABLE 4:
RELIABILITY SCORES FOR 15 FACTORS OF 16-PF REFLECTING
THE KR-8 SCORE
|
|
16-PF
FACTORS
|
KR-8
|
|
A
|
0.647
|
|
C
|
0.561
|
|
E
|
0.563
|
|
F
|
0.662
|
|
G
|
0.661
|
|
H
|
0.741
|
|
I
|
0.585
|
|
L
|
0.487
|
|
M
|
0.353
|
|
N
|
0.352
|
|
O
|
0.549
|
|
Q1
|
0.370
|
|
Q2
|
0.631
|
|
Q3
|
0.476
|
|
Q4
|
0.720
|
|
|
SOURCE: Prinsloo
1991:23
|
3.2.5 Procedure
The Discus and the 16-PF were administered by trained and
registered psychologists. The marking and interpretation of
the 16-PF questionnaires were done manually by the researcher,
a registered psychologist, and by psychologists from the HSRC.
3.2.6 Statistical Analysis
Pearson's product-moment correlation coefficient was computed,
using the SAS-system to determine a correlation between the
identified fifteen 16-PF factors and the Discus dimensions.
3.2.7 Results
The 120 questionnaires that were returned were statistically
analysed. Scores for each of the fifteen 16-PF factors as well
as the Discus dimensions were correlated. The individual Discus
variable scores were then correlated with all the fifteen factors
of the 16-PF, resulting in significant correlations at 1% level
of significance and at 5% level of significance. The results
of these findings are reflected in tables 5A (p-values) and
5B (r-values).
TABLE
5A: COMPARISON BETWEEN THE DISCUS DIMENSIONS AND THE
FIFTEEN FACTORS OF THE 16-PF. PEARSON'S PRODUCT-MOMENT
CORRELATION COEFFICIENT
(5% LEVEL OF SIGNIFICANCE)
(1% LEVEL OF SIGNIFICANCE)
p-values
|
|
Discus Dimension
|
16-PF Factor
|
1% Level of Significance
(99%)
|
16-PF Factor
|
5% Level of Significance
(95%)
|
|
Dominance
|
Q1
X (Q2, E)
X (G, L, Q1)
|
0.0004
0.0003
0.0083
|
E
Q2
-I
|
0.0141
0.0331
0.0110
|
|
Influence
|
A
-Q2
H
|
0.0011
0.0011
0.0070
|
F
-Q3
|
0.0146
0.0426
|
|
Steadiness
|
None
|
None
|
-E
-Q1
|
0.0363
0.0231
|
|
Compliance
|
-E
Q2
-F
-H
|
0.0095
0.0092
0.0045
0.0025
|
-G
O
|
0.0244
0.0446
|
TABLE
5B: COMPARISON BETWEEN THE DISCUS DIMENSIONS AND THE
16-PF FACTORS
r-values |
|
Discus Dimension
|
16-PF Factor
|
1% Level of Significance
r-values
|
16-PF Factor
|
5% Level of Significance
r-values
|
|
Dominance
|
Q1
X (Q2, E)
X (G, L, Q1)
|
0.32128
0.32846
0.24180
|
E
Q2
-I
|
0.22442
0.19551
0.23320
|
|
Influence
|
A
-Q2
H
|
0.29825
0.29593
0.24791
|
F
-Q3
|
0.22519
0.18776
|
|
Steadiness
|
None
|
None
|
-E
-Q1
|
0.19215
0.20907
|
|
Compliance
|
-E
Q2
-F
-H
|
0.23678
0.23768
0.26000
0.27583
|
-G
O
|
0.20715
0.18529
|