PsychologicalReports, 1990, 67, 1091-1100. O Psychological Reports 1990
DEVELOPMENT OF T H E TRUST I N PHYSICIAN SCALE: A MEASURE TO ASSESS INTERPERSONAL TRUST I N PATIENT-PHYSICIAN RELATIONSHIPS ' LYNDA A. ANDERSON AND ROBERT F. DEDRICK The University of Michigan Summary.-Trust is widely acknowledged as an essential ingredient in patientphysician relationships. Given a dearth of situation-specific measures designed to quantify patients' trust in their physicians, we set out to develop an instrument to assess a patient's interpersonal trust in his physician. Findings from two studies are reported describing the development and validation of the Trust in Physician scale. Study 1 of 160 participants provided preliminary support for the reliability (Cronbach alpha = ,901 and construct validity of the 11-item scale. Study 2, a replication study of 106 participants, supplied further evidence of the reliability and validity of the scale. Cronbach alpha was .85. Trust was significandy related to patients' desires for control in their clinical interactions and subsequent satisfaction with care. Research and clinical applications of the Trust in Physician scale are discussed.
The amount of control exerted by clinicians and patients in medical interactions has long been viewed as a critical aspect of health care (Seeman & Evans, 1962). Within the area of managing chronic disease, concern has turned toward patients' desired roles in their medical interactions. Numerous studies document the importance of patients' desires for information and involvement in care (Beisecker, 1988; Cassileth, Zupkis, Sutton-Smith, & March, 1980; Krantz, Baum, & Wideman, 1980; Smith, Wallston, Wallston, Forsberg, & King, 1984) as well as expectations about control (Wallston & Wallston, 1981). However, little is known regarding the factors that may influence patients' desires for or expectancies about control in health care. Most studies tend to focus on the effects of various patient-related demographic variables (e.g., age, sex) on desires for control and have not attended to the interpersonal aspects of patient-clinician relationships. One important construct in patient-clinician relationships that may be related to patients' desires for control is interpersonal trust. Although trust is widely acknowledged as an essential ingredient in patient-clinician relationships (Katz, 1984), there is no accepted measure of this construct. The most widely used measure of interpersonal trust is Rotter's 25-item Interpersonal Trust Scale (Rotter, 1967). This self-report measure assesses an individual's generalized trust in other people and is not specific to a particular situation or person. I n view of the lack of situation-specific measures quantifying a 'Requests for reprints should be sent to Lynda A. Anderson, De artment of Health Behavior and Health Education, School of Public Health, The University o r Michigan, 1420 Washington Heights, Ann Arbor, Michigan 48109-2029.
1092
L. A. ANDERSON & R. F. DEDRICK
person's trust within the domain of medical care, we set out to develop an instrument to assess a patient's interpersonal trust in his physician. We reasoned that a valid measure of interpersonal trust would be useful in understanding patients' desires for control as well as for explaining patients' behaviors related to management of dness. For the purposes of t h ~ sresearch, interpersonal trust is defined as a person's belief that the physician's words and actions are credible and can be relied upon. According to this definition, a patient who trusts his physician believes that his physician will act in his best interest and will provide support and assistance concerning treatment and medical care. This definition refers to trust within the ongoing relationship (process) rather than trust in a physician's ability to affect health outcomes positively. This definition is based on the work of Wallston, Wallston, and Gore (1973) who developed a measure of nurses' trust of patients and contrasts with the work that conceptualizes trust as the physicians' capacity to influence health outcomes positively (Carerinicchio, 1979). Although these two aspects of trust should theoretically be related, trust regarding the interpersonal aspects of the relationship is believed to play a major role in patients' desires for control in the therapeutic process. I n conceptualizing the construct of trust, the duality of the consequences of interpersonal trust must be considered. O n the one hand, trust makes possible an openness of communication that facilitates the exchange of information and feelings (Johnson & Noonan, 1972). Conversely, when taken to an extreme, unquestioned trust in clinicians may discourage or hinder patients from acting autonomously and taking an active role in their own health care (Waterman, 1981). As a result, positive as well as potentially negative consequences of trust should be considered. This paper describes the development of an instrument to assess each patient's interpersonal trust in his primary care physician within the context of the management of chronic disease. The first study provides data on the development of the scale. The second study provides additional data regarding the validity of the instrument.
Method Stage 1: Item generation.-The first step in constructing the measure was to generate a number of statements designed to assess a patient's trust in his physician. A number of instruments were reviewed (Rotter, 1967; Wallston, et al., 1973), and interviews were conducted with groups of patients and various health care providers as part of this process. Items were written to refer to a patient's primary care provider rather than to physicians in general. Three dimensions of trust were assessed: dependability of the physician
SCALE: TRUST IN PHYSICIAN
1093
("looks out" for the patient's best interest), confidence in the physician's knowledge and skills, and confidentiahty and reliability of information between the physician and the patient. Twenty-five items were generated in this process: 11 items reflected dependab~lit~, 9 referred to confidence, and 5 tapped confidentiality of information. Eight items were negatively worded, and 17 items were positively worded. Positively and negatively worded statements were interspersed to avoid response set bias. Trust items were presented in a five-point Likert format, with response options ranging from "strongly agree" to "strongly disagree." Stage 2: Item analysis.-The primary goals of this stage were twofold. The first was to identify a suitable set of items to measure interpersonal trust in a physician. The second was to examine the correlations between the resultant scale and other theoretically related constructs as preliminary evidence of construct validity. This research was conducted at an outpatient clinic in the Veterans Administration Medical Center in Fayetteville, North Carolina and was part of a larger study examining patients' desires for control in their medical care. Data were collected over a 6-mo. period. Each patient who attended the outpatient clinic was assigned a specific provider and subsequently received primary care from that provider. Patients were drawn from the clinics of eight staff physicians who were holding outpatient clinics during the study period. Patients eligible to participate had to have a diagnosis of noninsulin-dependent diabetes mellitus, have seen their physicians on at least one prior occasion, and be free of severe cognitive or communicative deficits as determined by reviews of medical records. Of the 177 patients asked to participate, 14 (8%) declined. Data from three respondents were excluded because the respondents did not comprehend the questions, i.e., the person either agreed or disagreed with all questions posed. The final sample included 160 patients. Respondents had completed an average of 11.8 yr. of formal education (SD = 2.9); all were men and had a mean age of 55.2 yr. (SD = 10.5). Most were married (78%), and 56.3% were white. Individuals who consented to the study participated in a face-to-face interview conducted outside the clinic in a private interviewing room. The interview schedule included demographic and treatment information, the 25 items developed to assess interpersonal trust in a physician, the Multidimensional Health Locus of Control scales, Form A (Wallston, Wallston, & DeVelLis, 1978) and an abbreviated 9-item version of the Marlowe-Crowne Social Desirability Scale (Strahan & Gerbasi, 1972). The Multidimensional Health Locus of Control scales were used to assess patients' beliefs about who or what determines health outcomes (Wallston, et al., 1978). Health locus of control is conceived as a rnultidi-
1094
L.A. ANDERSON
&
R. F. DEDRICK
mensional construct with three theoretical dimensions reflecting the extent to which an individual perceives that health outcomes are dependent upon: (a) one's own action (internal health locus of control), (b) the actions of powerful other people (powerful-others health locus of control), and (c) luck, fate or chance (chance health locus of control). These scales have been used to characterize the health locus of control beliefs in various subpopulations, including healthy adults and patients with chronic health conditions. The scales have an acceptable level of internal consistency and are also relatively stable over time for persons whose health circumstances remain constant (Wallston & Wdston, 1981). Items were answered using a 6-point format, ranging from "strongly agree" to "strongly disagree." The abbreviated version of the Marlowe-Crowne Social Desirability Scale (Strahan & Gerbasi, 1972) was used to assess an individual's need for approval by responding in a socially desirable or appropriate manner. The scale has demonstrated reliability. Items were answered using a 7-point format, ranging from "the statement does not apply to me at all" to "the statement always applies to me." Results An item analysis of the 25 trust items was conducted and items meeting the following criteria were retained: (a) a relatively high variance and so not restricted in range and (b) a correlation above .40 with the sum of the other items. Thirteen items met both criteria. Further inspection of the items by an additional evaluator indicated that one of the items ("I feel confident in my doctor's ability to make me well") focused more on outcome rather than process and a second item ("I would recommend my doctor to my family or friends") focused on satisfaction rather than trust in the relationship. To assure conceptual clarity these two items were eliminated. Table 1 presents the items of the trust scale as well as corrected item-to-total correlations. Three items were negatively worded and eight were positively worded. The internal consistency of the scale, as measured by Cronbach alpha (1951), was .90. Given the brevity of the scale along with the high internal consistency, the items were not subjected to factor analysis. As shown in Table 2, age and education were significantly related to interpersonal trust. Older patients and patients who had less formal education tended to express more trust in their physicians. Race was not significantly related to trust (F,,,,, = 0.9, p > .05). Furthermore, fasting blood glucose, an indicator of metabolic control (outcome), was not significantly related to trust ( r = .05, p > .05). Preliminary evidence of the construct validity of the trust scale was collected by comparing the scores obtained on the trust scale with scores obtained on the Multidimensional Health Locus of Control scales. Although
1095
SCALE: TRUST I N PHYSICIAN
outcomes (as assessed by these scales) are distinct from processes (as tapped by the trust scale), it was anticipated that trust would be positively related to the powerful-others health locus of control subscale. The scores on the Trust in Physician scale were moderately correlated with the scores on the powerful-others subscale (r = .28, p < .01), however, they shared less than 8% of the variance. Associations between trust and internal locus of control (T= -.07, p > .05) and trust and chance locus of control (r = .16, p < .05) were relatively weak, indicating that the trust scale and health locus of control are relatively distinct constructs. Finally, scores on the Trust in Physician scale were moderately correlated with social desirability (r = .3 1, p < .01). TABLE 1 MEANS,STANDARD DEVIATIONS, AND ITEM-TO-TOTAL COWLATIONSFOR I m s : STUDIES1 AND 2 TRUSTIN PHYSICJAN
1. I doubt that myd doctor really cares about me as a person. 2. My doctor is usually considerate of my needs and puts them first. 3. I trust my doctor so much I always try to follow his/her advice. 4. If my doctor tells me something is so, then it must be true. 5. I sometimes distrust my doctor's opinion and would like a second one.d 6. I trust my doctor's judgments about my medical care. 7. I feel my doctor does not do everything helshe should for my medical care.d 8. Itrust my doctor to put my medical needs above all other considerations when treating- my. medical problems. 9. My doctor is a real expert in taking care of medical problems Iike mine. 10. I crust my doctor to teu me if a mistake was made about my treatment. 11. 1 sometimes worry that my doctor may not keep the information we discuss totally private.d
SDb
M'
Item
Item-to-Total Correlation' 1 2
1
2
1
2
4.33
4.76
0.93
0.54
.64
.57
4.37
4.84
0.98
0.44
.68
.51
4.47
4.77
0.79
0.50
.67
.56
4.16
4.48
1.05
0.89
.65
.56
4.23
4.51
0.85
0.69
.59
.66
4.50
4.79
0.81
0.64
.70
.52
4.28
4.42
1.04
1.03
.61
.52
4.48
4.77
0.87
0.57
.67
.41
4.40
4.68
0.89
0.71
.68
.72
4.57
4.63
0.77
0.81
.60
.53
4.34
4.67
0.88
0.60
.63
.61
Note.-Verbatim instructions may be obtained from the first author. 'Means are from Studies 1 and 2, respectively. bStandard deviations are from Studies 1 and 2, respectively. 'Corrected item-to-total factor correlations are from Studies 1 and 2, respectively. dNegatively worded item.
In summary, psychometric analyses involving 160 patients provided preliminary support for the reliability and vahdity of the 11-item instrument entitled Trust in Physician scale. These findings were tested on a second in-
1096
L. A. ANDERSON & R. F. DEDRICK
dependent sample of patients to see whether the internal consistency remained high and to supply further evidence regarding the validity of the instrument. TABLE 2 ZERO-ORDER PEARSON CORRELATIONS FOR SCORESON SCALE,TRUSTIN PHYSICIAN, A N D DEMOGRAPHIC AND TREATMENT V ~ L E SSTUDIES : 1 AND 2 - - -
Age Study 1 Demographic Variables r with Trust n M
SD Range
.la' 159 55.2
10.5 27-82
Study 2 .12
103 60.9 9.7 24-90
Duration of Diabetes (yr.) Study 1 Study 2 Treatment Variables r with Trust n M
n a'
na
-. 11
103
-- --- - --
Education Study 1 Study 2
-.24b 160 11.8 2.9 2-16
-.08 103 10.3 3.5 4-19
Fasting Blood Sugar Level (mg %) Study 1 Study 2
.05
.12
141
90 na 13.6 191.6 189.8 SD na 9.0 91.5 72.5 Range na 0.08-40 67-841 36-408 Note.-For all measures, higher scores reflect more of the attribute indicated by variable name. 'p
DEVELOPMENT OF T H E TRUST I N PHYSICIAN SCALE: A MEASURE TO ASSESS INTERPERSONAL TRUST I N PATIENT-PHYSICIAN RELATIONSHIPS ' LYNDA A. ANDERSON AND ROBERT F. DEDRICK The University of Michigan Summary.-Trust is widely acknowledged as an essential ingredient in patientphysician relationships. Given a dearth of situation-specific measures designed to quantify patients' trust in their physicians, we set out to develop an instrument to assess a patient's interpersonal trust in his physician. Findings from two studies are reported describing the development and validation of the Trust in Physician scale. Study 1 of 160 participants provided preliminary support for the reliability (Cronbach alpha = ,901 and construct validity of the 11-item scale. Study 2, a replication study of 106 participants, supplied further evidence of the reliability and validity of the scale. Cronbach alpha was .85. Trust was significandy related to patients' desires for control in their clinical interactions and subsequent satisfaction with care. Research and clinical applications of the Trust in Physician scale are discussed.
The amount of control exerted by clinicians and patients in medical interactions has long been viewed as a critical aspect of health care (Seeman & Evans, 1962). Within the area of managing chronic disease, concern has turned toward patients' desired roles in their medical interactions. Numerous studies document the importance of patients' desires for information and involvement in care (Beisecker, 1988; Cassileth, Zupkis, Sutton-Smith, & March, 1980; Krantz, Baum, & Wideman, 1980; Smith, Wallston, Wallston, Forsberg, & King, 1984) as well as expectations about control (Wallston & Wallston, 1981). However, little is known regarding the factors that may influence patients' desires for or expectancies about control in health care. Most studies tend to focus on the effects of various patient-related demographic variables (e.g., age, sex) on desires for control and have not attended to the interpersonal aspects of patient-clinician relationships. One important construct in patient-clinician relationships that may be related to patients' desires for control is interpersonal trust. Although trust is widely acknowledged as an essential ingredient in patient-clinician relationships (Katz, 1984), there is no accepted measure of this construct. The most widely used measure of interpersonal trust is Rotter's 25-item Interpersonal Trust Scale (Rotter, 1967). This self-report measure assesses an individual's generalized trust in other people and is not specific to a particular situation or person. I n view of the lack of situation-specific measures quantifying a 'Requests for reprints should be sent to Lynda A. Anderson, De artment of Health Behavior and Health Education, School of Public Health, The University o r Michigan, 1420 Washington Heights, Ann Arbor, Michigan 48109-2029.
1092
L. A. ANDERSON & R. F. DEDRICK
person's trust within the domain of medical care, we set out to develop an instrument to assess a patient's interpersonal trust in his physician. We reasoned that a valid measure of interpersonal trust would be useful in understanding patients' desires for control as well as for explaining patients' behaviors related to management of dness. For the purposes of t h ~ sresearch, interpersonal trust is defined as a person's belief that the physician's words and actions are credible and can be relied upon. According to this definition, a patient who trusts his physician believes that his physician will act in his best interest and will provide support and assistance concerning treatment and medical care. This definition refers to trust within the ongoing relationship (process) rather than trust in a physician's ability to affect health outcomes positively. This definition is based on the work of Wallston, Wallston, and Gore (1973) who developed a measure of nurses' trust of patients and contrasts with the work that conceptualizes trust as the physicians' capacity to influence health outcomes positively (Carerinicchio, 1979). Although these two aspects of trust should theoretically be related, trust regarding the interpersonal aspects of the relationship is believed to play a major role in patients' desires for control in the therapeutic process. I n conceptualizing the construct of trust, the duality of the consequences of interpersonal trust must be considered. O n the one hand, trust makes possible an openness of communication that facilitates the exchange of information and feelings (Johnson & Noonan, 1972). Conversely, when taken to an extreme, unquestioned trust in clinicians may discourage or hinder patients from acting autonomously and taking an active role in their own health care (Waterman, 1981). As a result, positive as well as potentially negative consequences of trust should be considered. This paper describes the development of an instrument to assess each patient's interpersonal trust in his primary care physician within the context of the management of chronic disease. The first study provides data on the development of the scale. The second study provides additional data regarding the validity of the instrument.
Method Stage 1: Item generation.-The first step in constructing the measure was to generate a number of statements designed to assess a patient's trust in his physician. A number of instruments were reviewed (Rotter, 1967; Wallston, et al., 1973), and interviews were conducted with groups of patients and various health care providers as part of this process. Items were written to refer to a patient's primary care provider rather than to physicians in general. Three dimensions of trust were assessed: dependability of the physician
SCALE: TRUST IN PHYSICIAN
1093
("looks out" for the patient's best interest), confidence in the physician's knowledge and skills, and confidentiahty and reliability of information between the physician and the patient. Twenty-five items were generated in this process: 11 items reflected dependab~lit~, 9 referred to confidence, and 5 tapped confidentiality of information. Eight items were negatively worded, and 17 items were positively worded. Positively and negatively worded statements were interspersed to avoid response set bias. Trust items were presented in a five-point Likert format, with response options ranging from "strongly agree" to "strongly disagree." Stage 2: Item analysis.-The primary goals of this stage were twofold. The first was to identify a suitable set of items to measure interpersonal trust in a physician. The second was to examine the correlations between the resultant scale and other theoretically related constructs as preliminary evidence of construct validity. This research was conducted at an outpatient clinic in the Veterans Administration Medical Center in Fayetteville, North Carolina and was part of a larger study examining patients' desires for control in their medical care. Data were collected over a 6-mo. period. Each patient who attended the outpatient clinic was assigned a specific provider and subsequently received primary care from that provider. Patients were drawn from the clinics of eight staff physicians who were holding outpatient clinics during the study period. Patients eligible to participate had to have a diagnosis of noninsulin-dependent diabetes mellitus, have seen their physicians on at least one prior occasion, and be free of severe cognitive or communicative deficits as determined by reviews of medical records. Of the 177 patients asked to participate, 14 (8%) declined. Data from three respondents were excluded because the respondents did not comprehend the questions, i.e., the person either agreed or disagreed with all questions posed. The final sample included 160 patients. Respondents had completed an average of 11.8 yr. of formal education (SD = 2.9); all were men and had a mean age of 55.2 yr. (SD = 10.5). Most were married (78%), and 56.3% were white. Individuals who consented to the study participated in a face-to-face interview conducted outside the clinic in a private interviewing room. The interview schedule included demographic and treatment information, the 25 items developed to assess interpersonal trust in a physician, the Multidimensional Health Locus of Control scales, Form A (Wallston, Wallston, & DeVelLis, 1978) and an abbreviated 9-item version of the Marlowe-Crowne Social Desirability Scale (Strahan & Gerbasi, 1972). The Multidimensional Health Locus of Control scales were used to assess patients' beliefs about who or what determines health outcomes (Wallston, et al., 1978). Health locus of control is conceived as a rnultidi-
1094
L.A. ANDERSON
&
R. F. DEDRICK
mensional construct with three theoretical dimensions reflecting the extent to which an individual perceives that health outcomes are dependent upon: (a) one's own action (internal health locus of control), (b) the actions of powerful other people (powerful-others health locus of control), and (c) luck, fate or chance (chance health locus of control). These scales have been used to characterize the health locus of control beliefs in various subpopulations, including healthy adults and patients with chronic health conditions. The scales have an acceptable level of internal consistency and are also relatively stable over time for persons whose health circumstances remain constant (Wallston & Wdston, 1981). Items were answered using a 6-point format, ranging from "strongly agree" to "strongly disagree." The abbreviated version of the Marlowe-Crowne Social Desirability Scale (Strahan & Gerbasi, 1972) was used to assess an individual's need for approval by responding in a socially desirable or appropriate manner. The scale has demonstrated reliability. Items were answered using a 7-point format, ranging from "the statement does not apply to me at all" to "the statement always applies to me." Results An item analysis of the 25 trust items was conducted and items meeting the following criteria were retained: (a) a relatively high variance and so not restricted in range and (b) a correlation above .40 with the sum of the other items. Thirteen items met both criteria. Further inspection of the items by an additional evaluator indicated that one of the items ("I feel confident in my doctor's ability to make me well") focused more on outcome rather than process and a second item ("I would recommend my doctor to my family or friends") focused on satisfaction rather than trust in the relationship. To assure conceptual clarity these two items were eliminated. Table 1 presents the items of the trust scale as well as corrected item-to-total correlations. Three items were negatively worded and eight were positively worded. The internal consistency of the scale, as measured by Cronbach alpha (1951), was .90. Given the brevity of the scale along with the high internal consistency, the items were not subjected to factor analysis. As shown in Table 2, age and education were significantly related to interpersonal trust. Older patients and patients who had less formal education tended to express more trust in their physicians. Race was not significantly related to trust (F,,,,, = 0.9, p > .05). Furthermore, fasting blood glucose, an indicator of metabolic control (outcome), was not significantly related to trust ( r = .05, p > .05). Preliminary evidence of the construct validity of the trust scale was collected by comparing the scores obtained on the trust scale with scores obtained on the Multidimensional Health Locus of Control scales. Although
1095
SCALE: TRUST I N PHYSICIAN
outcomes (as assessed by these scales) are distinct from processes (as tapped by the trust scale), it was anticipated that trust would be positively related to the powerful-others health locus of control subscale. The scores on the Trust in Physician scale were moderately correlated with the scores on the powerful-others subscale (r = .28, p < .01), however, they shared less than 8% of the variance. Associations between trust and internal locus of control (T= -.07, p > .05) and trust and chance locus of control (r = .16, p < .05) were relatively weak, indicating that the trust scale and health locus of control are relatively distinct constructs. Finally, scores on the Trust in Physician scale were moderately correlated with social desirability (r = .3 1, p < .01). TABLE 1 MEANS,STANDARD DEVIATIONS, AND ITEM-TO-TOTAL COWLATIONSFOR I m s : STUDIES1 AND 2 TRUSTIN PHYSICJAN
1. I doubt that myd doctor really cares about me as a person. 2. My doctor is usually considerate of my needs and puts them first. 3. I trust my doctor so much I always try to follow his/her advice. 4. If my doctor tells me something is so, then it must be true. 5. I sometimes distrust my doctor's opinion and would like a second one.d 6. I trust my doctor's judgments about my medical care. 7. I feel my doctor does not do everything helshe should for my medical care.d 8. Itrust my doctor to put my medical needs above all other considerations when treating- my. medical problems. 9. My doctor is a real expert in taking care of medical problems Iike mine. 10. I crust my doctor to teu me if a mistake was made about my treatment. 11. 1 sometimes worry that my doctor may not keep the information we discuss totally private.d
SDb
M'
Item
Item-to-Total Correlation' 1 2
1
2
1
2
4.33
4.76
0.93
0.54
.64
.57
4.37
4.84
0.98
0.44
.68
.51
4.47
4.77
0.79
0.50
.67
.56
4.16
4.48
1.05
0.89
.65
.56
4.23
4.51
0.85
0.69
.59
.66
4.50
4.79
0.81
0.64
.70
.52
4.28
4.42
1.04
1.03
.61
.52
4.48
4.77
0.87
0.57
.67
.41
4.40
4.68
0.89
0.71
.68
.72
4.57
4.63
0.77
0.81
.60
.53
4.34
4.67
0.88
0.60
.63
.61
Note.-Verbatim instructions may be obtained from the first author. 'Means are from Studies 1 and 2, respectively. bStandard deviations are from Studies 1 and 2, respectively. 'Corrected item-to-total factor correlations are from Studies 1 and 2, respectively. dNegatively worded item.
In summary, psychometric analyses involving 160 patients provided preliminary support for the reliability and vahdity of the 11-item instrument entitled Trust in Physician scale. These findings were tested on a second in-
1096
L. A. ANDERSON & R. F. DEDRICK
dependent sample of patients to see whether the internal consistency remained high and to supply further evidence regarding the validity of the instrument. TABLE 2 ZERO-ORDER PEARSON CORRELATIONS FOR SCORESON SCALE,TRUSTIN PHYSICIAN, A N D DEMOGRAPHIC AND TREATMENT V ~ L E SSTUDIES : 1 AND 2 - - -
Age Study 1 Demographic Variables r with Trust n M
SD Range
.la' 159 55.2
10.5 27-82
Study 2 .12
103 60.9 9.7 24-90
Duration of Diabetes (yr.) Study 1 Study 2 Treatment Variables r with Trust n M
n a'
na
-. 11
103
-- --- - --
Education Study 1 Study 2
-.24b 160 11.8 2.9 2-16
-.08 103 10.3 3.5 4-19
Fasting Blood Sugar Level (mg %) Study 1 Study 2
.05
.12
141
90 na 13.6 191.6 189.8 SD na 9.0 91.5 72.5 Range na 0.08-40 67-841 36-408 Note.-For all measures, higher scores reflect more of the attribute indicated by variable name. 'p
