ABSTRACT:
INTRODUCTION: Dentistry has evolved into a highly stressful profession. Numerous studies have assessed stress in dental environment in Western countries. Finding of these studies cannot be extrapolated on developing countries like India due to cross-cultural differences. Hence, the present study was conducted to ascertain the validity and reliability of Stress Measurement Scale used to assess stress among students and staff in a dental institution in India. MATERIALS & METHODS: Items for the Stress Measurement Scale were generated from four sources: theory, research, observation and expert opinion. 110 items were generated and the questionnaire was pre-tested on peers and study subjects. The questionnaire was modified based on the inputs obtained by pre�testing. The questionnaire was tested on dental undergraduate and postgraduate students and staff members in a dental institution in India. RESULTS: A total of 111 study subjects responded, out of which 52.89% were females. Reliability estimates indicate that Cronbach's alpha was 0.9265 and split half reliability was 0.9449. Construct validity was 0.9265 and concurrent validity of the scale along with that of the Dental Environment Stress (DES) scale was 0.6857. Test-retest reliability was found to be 0.7612. CONCLUSIONS: Stress measurement scale developed to assess stress among dental students & staff is a reliable & valid instrument and it might be an useful tool in measuring stress among dental students and staff in the Indian context.
Official Journal of the Association for Dental Education in Europe
INTRODUCTION:
Stress is defined as the strain that accompanies a demand perceived to be either
challenging (positive) or threatening (negative) and, depending on the appraisal, either
adaptive or debilitating1. It has been described as external demands (physical or mental)
on an individual�s physical and psychological well-being2. It is said to be a double edged
sword, i.e., it can be a source of motivation for individuals to achieve greater heights or it
may reduce the individual to ineffectiveness3, 4.
Dentistry has evolved into a highly demanding and competitive profession. There
is a need to acquire diverse proficiencies like theoretical knowledge, clinical
competencies and interpersonal skills5. Although a few investigators have reported that
dentists perceive themselves as being in good physical health6-9 it has been widely
acknowledged that dentistry is associated with high levels of stress. Dentistry is stressful
not only for dentists but for the entire dental team2,10-16. It has also been reported that
dentists suffer from especially high degrees of stress even when compared with other
health professionals17, 18.
The reaction of an individual to stress is influenced by self-cognitions, i.e., a
person�s system of beliefs and attitudes19, 20, 21. It has also been reported that there are
variations in the response to stress experienced by individuals. Not only is there variation
between individuals at different times of the day, but there is also variation between
different occupations and even between different occupations and even between
specialists within one specific occupation22, 23. This makes stress measurement not only
challenging, but also interesting.
Official Journal of the Association for Dental Education in Europe
In one of the first studies on dental student stress described in the scientific
literature, Goldstein24 adapted a stress questionnaire that was used amongst medical
students to the dental school setting. From the Goldstein study onwards, more and more
studies investigating dental student stress appeared in the literature. Different sets of
items were used in various questionnaires, as were different types of answering scales.
Garbee et al25 started the development of a questionnaire to monitor dental student stress,
which was further refined by Grandy et al26 in to the Dental environment Stress (DES)
questionnaire27 .
The practice of dentistry in India has witnessed changes in the recent past with the
sudden mushrooming of around 291 dental institutions across the country28 . These
institutions are providing oral health care to a large number of populace and they
constitute an important means of delivery of oral health care in India.
Traditionally, Indian society is considered to have stronger familial values and
greater respect for elders, with the younger individuals implicitly heeding to the advice of
the elders. In the past few decades, Indian society has witnessed social and economic
upheavals and it is currently in a state of transition. There is a need for dental educators to
understand how stress factors can be affected by changing socio-cultural values29 .
New stressors might be emerging and older ones might be evolving in the field of
dentistry and dental education in India. As the perception of stress is influenced by a
multitude of factors, the findings of studies in Western countries cannot necessarily be
applied to developing countries like India due to cross-cultural differences. Hence, there
is a need to develop a stress measurement scale for dental students and staff which is
specific for the Indian context.
Official Journal of the Association for Dental Education in Europe
Therefore, the present study was conducted to ascertain the reliability and validity
of Stress Measurement Scale that assesses stress among dental students and staff in a
dental institution in India.
MATERIALS AND METHODS:
A questionnaire to assess stress among dental students and staff in India was
developed for the present study. The items for the Stress Measurement Scale were
generated from 4 sources: theory, research, observation and expert opinion30. The Dental
Environment Stress (DES) scale developed by Garbee (1980) was adapted to the Indian
scenario.
A total of 110 items were generated and there were 11 domains in the
questionnaire. The responses to the items were based on a four-point Likert scale with
response options of 1 = not stressful, 2 = slightly stressful, 3 = moderately stressful and 4
= very stressful. A fifth possible response of not applicable was also provided. Matrix
question format was followed as all the items had same set of answer categories31 .
Prior to the start of the study, ethical clearance was obtained from the Institutional
Review Committee. The questionnaire was initially pre-tested on peers and a few study
subjects and it was modified based on the inputs obtained. The questionnaire was given
to 5 experts to determine the appropriateness and relevance of the items and also to
determine face validity.
The study subjects belonged to 3 categories, viz., undergraduate students,
postgraduate students and staff members. As validation studies require at least 30 study
subjects in each of the categories and the questionnaire had also to be re-administered to
Official Journal of the Association for Dental Education in Europe
The same study subjects after 2 weeks, the investigators included a greater number of
study subjects at the start of the study. The questionnaire was thus administered to 132
study subjects in a private dental institution in Karnataka, India. The original Dental
Environment Stress (DES) scale developed by Garbee (1980) was also administered to
the study subjects to determine concurrent validity.
Two weeks after the initial administration, the questionnaire was re-administered
to the same study subjects to assess test-retest reliability.
STATISTICAL ANALYSIS:
The questionnaire was first tested for reliability and then validity. In reliability,
the questionnaire was tested for test retest reliability and internal consistency reliability.
The latter included average inter-item correlation, average item total correlation, split-
half reliability and cronbach�s alpha. In validity, the questionnaire was assessed for face
validity, content validity (inter-item correlations), concurrent validity and construct
validity.
RESULTS:
The questionnaire was administered to 132 study subjects in a private dental
institution in Karnataka, India, out of which, 111 subjects responded. The response rate
was thus 91.66%. Among the study subjects, 50, 37 and 34 were undergraduate students,
postgraduate students and staff members respectively. A total of 52.89% were females.
Official Journal of the Association for Dental Education in Europe
Reliability estimates:
Cronbach's alpha was found to be 0.9265 and split half reliability was 0.9449. The
other reliability estimates further corroborate the results.
Validity estimates:
Face validity was determined by expert opinion and it involves non-statistical
evaluation judgment of the questionnaire. The square root of split half reliability can also
be considered as an indirect measure of validity and it was found to be 0.9720. This
method however, is not considered by many investigators to be an appropriate estimate of
validity.
Cronbach's alpha is considered to be an estimate of construct validity and it was
found to be 0.9265. The concurrent validity of the questionnaire along with that of the
Dental Environment Stress (DES) scale originally given by Garbee (1980) was found to
be 0.6857.
Statistical analysis revealed that the following 5 questions were of questionable
contribution: difficulty in learning preclinical & laboratory work, early starting
time/reaching on time in morning, lack of interest in dentistry, considering entering some
other field of work and attitude of female patients towards female students/staff.
Test-retest reliability ranged from 0.4052 (finances) to 0.8144 (patient care) and
the overall test-retest reliability for the entire scale was found to be 0.7612.
DISCUSSION:
Official Journal of the Association for Dental Education in Europe
It was the intention of the investigators to explore further into the issue of stress
among dental faculty and dental students in the Indian setup by the development of this
scale.
Questionnaire is defined as �a list of mimeographed or printed questions that is completed by or for a respondent�32. Once a measurement scale has been derived, one has to establish its reliability and validity before it is used. Reliability refers to the degree to which the results obtained by a measurement procedure can be replicated. Validity is derived from the Latin word validus, meaning strong and is an expression of the degree to which a measurement measures what is purports to measure33 .
The DES scale was put forth by Garbee et al in 1981, more than a quarter of a
decade ago. In view of the changes that have taken place in all spheres related to the
arena of dentistry, new stressors might be emerging and older ones might still be
evolving in the field of dentistry and dental education in India. The present stress
measurement scale might be an useful tool to probe these aspects related to stress in
dental setup in the Indian backdrop.
The original dental environment stress scale is a 38-item questionnaire while the
number of items in the present scale is 110. It is not uncommon to find instruments,
especially in the domain of behavioural sciences, in which the number of items is more
than hundred. As the number of items in an instrument increases, the time required to
answer by the respondents too increases. However, with the use of matrix questions
format, the time required to finish the present scale is considerably reduced.
It has been observed by investigators that longer tests (i.e., measures consisting of
more individual items) are more reliable than shorter ones, other things (particularly the
Official Journal of the Association for Dental Education in Europe
quality of items) being equal. A larger range of variation on the measured factor among
the individuals being tested also leads to higher reliability34. As the present scale had 110
items, increasing the items might lead to enhanced reliability of the scale.
The concurrent validity of the present scale with the DES scale was found to be
0.6857. It indicates that the present scale measures the same concepts as measured by the
DES scale. It implies that increasing the number of items to 110 has not lead
measurement of constructs other than that measured by the DES scale.
Matrix questions format can be used whenever the Likert response scales are used
as they have same set of answer categories to several questions. This format has a number
of advantages. First it uses space efficiently. This makes the questionnaire look more
compact when handing it to the respondents to answer it. Secondly, respondents will
probably find it faster to complete a set of questions presented in this fashion. Thirdly,
this format may increase the comparability of responses given to different questions for
the respondent as well as for the researcher. Because respondents can quickly review
their answers to earlier items in the set, they might choose between, say, �very stressful�
and �moderately stressful� by comparing the strength of response to their earlier response
in the set31 .
There are some dangers inherent in using this format as well. Its advantages may
encourage you to structure an item so that the responses fit into the matrix format when a
different, more idiosyncratic set of responses might be appropriate. Also, the matrix
question format can foster a response-set among some respondents, i.e., they may
develop a pattern of responding to the items. That would be especially likely if the set of
statements began with several that indicated a particular orientation with only a few later
Official Journal of the Association for Dental Education in Europe
ones representing the opposite orientation. Respondents might assume that all the
statements represented the same orientation and reading quickly, misread some of them,
thereby giving the wrong responses. This problem can be reduced somewhat by
alternating statements representing different orientations and by making all statements
short and clear31 .
Five questions of questionable contribution were: difficulty in learning preclinical
& laboratory work, early starting time/reaching on time in morning, lack of interest in
dentistry, considering entering some other field of work and attitude of female patients
towards female students/staff.
There is considerable difference between statistical significance and practical
significance. Our observation, experience and inputs during pre-testing and pilot testing
indicate that the 5 questions mentioned above were important stressors and they could not
be overlooked. Moreover, 5 questions were not affecting overall reliability & validity of
the questionnaire. Therefore, it was deemed important to include the 5 questions
mentioned above in the questionnaire.
Test-retest reliability of 0.7612 indicates that the scale was reliable over a period
of time.
The response options in the present scale were based on a 4-point Likert scale and
it also included a fifth possible option of �not applicable�. Like the DES scale, the
present scale could be administered to undergraduate and postgraduate students and to
staff members as well. The presence of the fifth option of �not applicable� makes the
present scale administrable to both students and staff members.
Official Journal of the Association for Dental Education in Europe
Certain items in the DES scale are not strictly related to dental environment.
Examples of such items include having children in the home, marital adjustment
problems, financial responsibilities, forced postponement of marriage or engagement,
discrimination due to race, class status, or ethnic group, having a dual role of wife/mother
or husband/father and dental student, etc. Similarly in the present scale, there are items
which do not per se relate to the dental environment. Stress in a phenomenon which can
be affected by a myriad of factors. Activities in the domestic front may directly
contribute to stress in the dental environment or they may sensitize the individual to
stress in the dental environment. Therefore, it might be essential to include such items in
the instrument.
The present scale incorporates questions which are specific to the female gender.
As compared to the DES scale, it has greater number of questions which deal with issues
related to the same. Traditionally, women in countries like India were relegated to the
role of housewives and were rarely venturing into areas which were considered to be
belonging to the male domain. With changing times and trends, women are now stepping
out of their houses and are seeking education and/or employment which can be said to be
on par with their male compatriots. They are thus expected to do the balancing act of
managing both family and profession. They might encounter individuals, both males and
females, who might be prejudiced or biased against women. Few questions were included
in the present scale to tap stressors associated with the same.
Like any other scale, the present scale is prone to various biases. These may
include social desirability or faking good, deviation or faking bad and yea-saying or
Official Journal of the Association for Dental Education in Europe
acquiescence biases. Scales which are scored on a continuum, like the Likert scales are
prone to biases like end-aversion bias, positive skew and the halo effect35 .
End-aversion bias, also referred to as the central tendency bias, refers to the
reluctance of some people to use the extreme categories of scale. Some individuals find it
difficult to make absolute judgments as situations without mitigating or extenuating
circumstances rarely occur. This can be overcome by avoiding absolute statements at the
end-points or by including �throw away� categories at the end-points, thereby increasing
the number of response options in the scale.
When responses are not evenly distributed over the range of alternatives and they
show a positive skew toward the favourable end, there is said to be positive skew or the
ceiling effect. This bias is even more evident when the instrument is administered to
students or staff. This may reflect the feeling that the �average� respondent is really quite
stressed and it becomes difficult to distinguish among various grades of excellence. This
can be dealt with by increasing the number of response options above the midpoint or at
the midpoint, depending upon the needs and philosophies of the programme.
Halo is a phenomenon first recognized first by Wells FL in the year 1907.
Judgments made on the individual�s aspects of a person�s performance are influenced by
the rater�s overall impression of the person. In the context of the present scale, responses
by the raters will be influenced by the rater�s overall impression of the institution or on
the faculty or on the entire educational system. Since stress perception is influenced by
various factors including faculty, institution and the entire educational system, there may
actually be a �true halo�. There may actually be real correlations among various issues.
More often than not, there may actually not be any correlations among various aspects as
Official Journal of the Association for Dental Education in Europe
the raters will be able to evaluate only a few dimensions of the pertinent issues. This is
referred to as the �illusory halo� or simply as the �halo effect�.
But since these aspects could not be incorporated in the present scale, the above
mentioned biases are inherent in the present scale. Proper ordering of the items and
formatting of the scale and proper instructions to the respondents, issuance of the
questionnaire in proper environment can but only partially offset these biases. Further
studies involving the present scale addressing the bias inherent within the scale is
essential.
CONCLUSIONS:
With dentistry widely being acknowledged as a stress-prone profession, there is a
growing interest among researchers and academicians alike in stress research in the last
few decades. The scales used to assess stress in the dental set-up were developed in the
Western countries, which might not be applicable in developing countries like India due
to cross cultural differences. Hence, a stress measurement scale was developed to assess
stress among dental students and staff in a dental institution in India. The Dental
Environment Stress (DES) scale was adapted to the Indian scenario. Results indicate that
the stress measurement scale developed to assess stress among dental students & staff is a
reliable & valid instrument. Concurrent validity indicates that it measures the same stress
as measured by Dental Environment Stress (DES) scale. The stress measurement scale
Official Journal of the Association for Dental Education in Europe
might be an useful tool in measuring stress among dental students and staff in the Indian
context.
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