Journal of Clinical Psychology in Medical Settings, Vol. 1, No. 2, 1994
Readability of Prescription Drug Labels by Older and Younger Adults J a n a n AI-Awar S m i t h e r I and Curt C. B r a u n 2
This experiment investigated the readability of medication labels using various combinations of fonts, sizes, and weights of print. Older and younger adult reading speeds and error rates for different print types were compared for both bottle and flat labels. Findings of the study indicated significant differences in readbTg speed, error rates, and subjective evaluations for print characteristics investigated. Furthermore, the effects of these print characteristics varied for different age groups. Implications of these findings for the design of medication labels for older adults are discussed. KEY WORDS: geriatrics; health psychology; pharmacy; compliance, reading legibility.
INTRODUCTION The elderly are the largest consumers of medication, expending 25% of all written prescriptions (Moore, Kalu, & Yavaprabbas, 1983). By the year 2030, this expenditure is expected to rise to about 40%. At the same time, medication noncompliance among the elderly has become a major health care concern (Morrow, Leirer, & Sheikh, 1988). Many researchers have investigated elderly noncompliance, with most of these studies focusing on issues such as the magnitude of noncompliance and the effects of instruction and labelling techniques (Leirer, Morrow, Pariante, & Sheik, 1988; Morrell, Park, & P o o n , 1990; Park, Morrell, Frieske, & Kincaid, 1992). Although some research addresses the readability of the medication label as a potential source of noncompliance, only one study (Zuccollo & Liddell, 1985) evaluated the legibility of several typeIThe University of Central Florida, Orlando, Florida 32816. 2The University of Idaho, Moscow, Idaho 83843. 149
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faces. Findings from that study indicated that 60% of the elderly participants had difficulty reading the labels produced at a hospital pharmacy. The lack of empirical research in the area of label legibility is surprising since a patient's ability to read the information on a label is, arguably, one of the first steps necessary for medication compliance. Research with Younger Subjects Although few legibility studies have included older adults, researchers have addressed legibility with children and young adults. Findings by Paterson and Tinker (1940) and Tinker (1963) suggest that, for young adults, the minimum legible type size is 8 points, with little improvement in reading speed expected above 11 points. Vanderplas and Vanderplas (1980) found that performance decrements related to typeface selection occurred only when unusual styles such as Old English were used. Other print factors that could affect legibility include font weight (bold vs. nonbold), presence or absence of serifs (i.e., small curves at the ends of the strokes), and character width (proportional vs. nonproportional). A study by Krulee and Novy (1986) showed bold type to be superior to nonbold for reading individual words. Tinker (1963), however, found no difference between bold and roman (nonbold) types in terms of reading speed. Tinker (1963) also found that although his readers expressed a strong preference for serifed type, there were very few performance differences. Payne (1967) and Beldie, Pastoor, and Schwarz (1983) have demonstrated the superiority of proportional over nonproportional spacing with both printed and digital text. Generalizing to Older Subjects Findings of legibility studies with older adults do not replicate those with younger ones. Poulton (1959, 1969) indicated that performance of older adults was affected negatively by small print and low illumination. Vanderplas and Vanderplas (1980) found a greater reading speed for Century Schoolbook font than for Helvetica, which is considered the standard for warning labels (FMC Corporation, 1985). These researchers also recommended the use of the 12- to 14-point size range, as opposed to the 8to 12-point size range that is the typical choice for younger persons. They concluded that because of the interaction of style-size combinations, line width, and leading (spacing between lines), the choice of print for any particular material requires task specific investigation.
Prescription Label Readability
151
Despite these differences in research results, there are some published guidelines for legibility for geriatric individuals based on data collected with younger individuals (Ralph, 1982). Considering the well-documented, agerelated declines in visual abilities among older adults, however, it is unclear that these recommendations would be applicable for developing print guidelines for older adults. Furthermore, evidence suggests that task specific analyses are necessary to ensure the proper selection of print characteristics (Vanderplas & Vanderplas, 1980). The present research was designed to assess the effects of age, font type, size, and weight on the readability of prescription medication labels. It was hypothesized that the print characteristics investigated will affect reading performance and preference and that these effects will differ for individuals of different age groups.
EXPERIMENT 1 Method
Subjects. The subjects were 19 younger adults [9 males (mean age = 22.12, SD = 1.93) and 10 females (mean age = 28.5, SD = 6.93)] and 20 older adults, over the age of 65 [10 males (mean age = 69.8, SD = 5.94) and 10 females (mean age = 72.3, SD = 5.53)]. The older volunteers were recruited from a learning institute for elders within a university setting. Younger volunteers were recruited from undergraduate psychology classes. All subjects were prescreened for reading ability, cognitive functioning, and near visual acuity. To participate, subjects had to be reading at a minimum of an eighth-grade level, their scores on the Digit Symbol test of the WAIS-R had to fall within the normal range for their age group, and those subjects with low vision were required to wear their corrective lenses during the experiment. Design. The study was a 2 (age) x 2 (gender) x 3 (font) x 3 (size) x 2 (weight) mixed-model design. The between-subject factors were age (young, old) and gender (male, female). The within-subject factors were font (Courier, Century Schoolbook, Helvetica), size (9 point, 12 point, 14 point), and weight (Bold, Roman). Material. The materials used were 72 standard size medication bottles (20 dram), 72 hospital pharmacy labels, a demographic questionnaire, a reading abilities test, the Digit Symbol test from the WAIS-R, and a Titmus Vision Tester. The selection of print types used was based on a review of the literature, as well as a survey of fonts used in major Central Florida pharmacies (Courier, 9 point, Roman). Courier and Century Schoolbook are serif fonts,
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while Helvetica is a sans serif font. Century Schoolbook and Helvetica are proportional fonts, whereas Courier is a nonproportional font. The factorial combinations of font, size, and weight resulted in 18 label conditions. These conditions were then reproduced using four different sets of label information (LI). T h e LI sets were p r o d u c e d by the random assignment of the following pieces of information four times: (1) name of a physician, (2) name of a medication, (3) instructions, and (4) n u m b e r of refills. The end product of this process was four sets of 18 labeled medication bottles (see Table I). All labels were equated for content of information. Procedure. Subjects were first asked to complete the demographic questionnaire, a reading abilities test, and the Digit Symbol test. Next, each subject's near visual acuity was assessed. Each subject was then instructed to read the information on 18 labeled prescription bottles, one at a time, as quickly and accurately as possible. The order of presentation of the 18 bottles was randomized for each subject to reduce order effects. Before starting the experimental portion of the study, subjects were allowed to practice the procedure with three medication bottles. Subsequently, subjects were instructed to pick up a medication bottle and read the label information aloud. Time to read was measured in 0:01 of a second using a stopwatch. Subject accuracy was also recorded. After reading all the labels, subjects were instructed to look at each label again and to judge the print on a 7-point scale according to (1) ease of reading (very easy-very difficult), (2) clearness of type (very sharp-not at all sharp), and (3) appropriateness of size (too small-too large). Table 1. Examples of Font Type, Weight, and Size Point size Font
9
12
14
Bold Courier Century Schoolbook Helvetica
Refill
Refill
Refill
Refill
Refill"
Refill Refill
Refill
Refill Roman
Courier Century Schoolbook Helvetica
Refill b
Refill
Refill
Refill
Refill
Refill
Refill
Refill Refill
aRecommended font, size, and weight combination for use on bottles and flat labels. bprint type used by major Central Florida pharmacies.
Prescription Label Readability
153
Results
Reading Speed. A 2 x 2 x 3 x 3 x 2 mixed-model analysis of variance was performed on the reading speed data and indicated significant main effects for four independent variables: age, font, weight, and size (see Table II). Older adults were significantly slower than younger adults, and Roman weight was significantly slower to read than Bold. Range tests of the main effect of font indicated that Courier required significantly longer time to read than Helvetica and Century Schoolbook (p's < .0001). Similar range tests for size indicated that 9-point print required significantly more time to read than 12- and 14-point print (p's < .00001). The analysis also revealed several significant interactions. However, only those interactions that include age effects are included in this report (see Table II). Tests of simple effects for the weight × age interaction indicated no effects of weight for older adults. The three-way interaction of font x size x age was broken down by age group. Tests of simple effects performed on the separate interactions indicated that older adults performed best with the 12-point Century Schoolbook print. This interaction also indicated that 9-point was particularly slow with the Courier font, especially for the older subjects. Performance Errors. A similar A N O V A of subject error data indicated significant main effects for the three independent variables of age, font, and size (see Table II). Older adults committed more errors than their younger counterparts. Range tests indicated that more errors were committed with the Courier font than with Century Schoolbook or Helvetica (p's < .01) and that more errors were committed with the 9-point size than with the 12- or 14-point size (p's < .05). The analysis also revealed significant age interactions of font × age, weight x age, and font × weight x age (see Table II). Tests of simple effects for the font × age interaction indicated that older adults committed more errors with the Courier font than with Century Schoolbook or Helvetica (p's < .01) and that older adults committed more errors than younger adults with the Courier font (p's < .001). Furthermore, the weight x age interaction showed that older adults committed more errors with the Bold than the Roman print (p's < .01) and more errors with the Bold print than younger adults (p's < .001). The nature of this interaction indicated no effects of weight for younger adults. The three-way interaction was broken down by age group to form two font × weight interactions. Tests of simple effects of these interactions indicated that older adults committed more errors with the Courier Bold print than with the Courier Roman (p's < .001) and that older adults, when
2,68 1,34 2,68 1,34 2,68 2,70 2,70 2,68 2,68
Font (F) Weight (W) Size (S) W x A W x S x A Size (S) F x W x A
Font (F) Size (S)
Reading ease
Size
*p
Readability of Prescription Drug Labels by Older and Younger Adults J a n a n AI-Awar S m i t h e r I and Curt C. B r a u n 2
This experiment investigated the readability of medication labels using various combinations of fonts, sizes, and weights of print. Older and younger adult reading speeds and error rates for different print types were compared for both bottle and flat labels. Findings of the study indicated significant differences in readbTg speed, error rates, and subjective evaluations for print characteristics investigated. Furthermore, the effects of these print characteristics varied for different age groups. Implications of these findings for the design of medication labels for older adults are discussed. KEY WORDS: geriatrics; health psychology; pharmacy; compliance, reading legibility.
INTRODUCTION The elderly are the largest consumers of medication, expending 25% of all written prescriptions (Moore, Kalu, & Yavaprabbas, 1983). By the year 2030, this expenditure is expected to rise to about 40%. At the same time, medication noncompliance among the elderly has become a major health care concern (Morrow, Leirer, & Sheikh, 1988). Many researchers have investigated elderly noncompliance, with most of these studies focusing on issues such as the magnitude of noncompliance and the effects of instruction and labelling techniques (Leirer, Morrow, Pariante, & Sheik, 1988; Morrell, Park, & P o o n , 1990; Park, Morrell, Frieske, & Kincaid, 1992). Although some research addresses the readability of the medication label as a potential source of noncompliance, only one study (Zuccollo & Liddell, 1985) evaluated the legibility of several typeIThe University of Central Florida, Orlando, Florida 32816. 2The University of Idaho, Moscow, Idaho 83843. 149
1068.9583D4/0600-0149507.00/0© 1994PlenumPublishingCorporation
150
Smither and B r a u n
faces. Findings from that study indicated that 60% of the elderly participants had difficulty reading the labels produced at a hospital pharmacy. The lack of empirical research in the area of label legibility is surprising since a patient's ability to read the information on a label is, arguably, one of the first steps necessary for medication compliance. Research with Younger Subjects Although few legibility studies have included older adults, researchers have addressed legibility with children and young adults. Findings by Paterson and Tinker (1940) and Tinker (1963) suggest that, for young adults, the minimum legible type size is 8 points, with little improvement in reading speed expected above 11 points. Vanderplas and Vanderplas (1980) found that performance decrements related to typeface selection occurred only when unusual styles such as Old English were used. Other print factors that could affect legibility include font weight (bold vs. nonbold), presence or absence of serifs (i.e., small curves at the ends of the strokes), and character width (proportional vs. nonproportional). A study by Krulee and Novy (1986) showed bold type to be superior to nonbold for reading individual words. Tinker (1963), however, found no difference between bold and roman (nonbold) types in terms of reading speed. Tinker (1963) also found that although his readers expressed a strong preference for serifed type, there were very few performance differences. Payne (1967) and Beldie, Pastoor, and Schwarz (1983) have demonstrated the superiority of proportional over nonproportional spacing with both printed and digital text. Generalizing to Older Subjects Findings of legibility studies with older adults do not replicate those with younger ones. Poulton (1959, 1969) indicated that performance of older adults was affected negatively by small print and low illumination. Vanderplas and Vanderplas (1980) found a greater reading speed for Century Schoolbook font than for Helvetica, which is considered the standard for warning labels (FMC Corporation, 1985). These researchers also recommended the use of the 12- to 14-point size range, as opposed to the 8to 12-point size range that is the typical choice for younger persons. They concluded that because of the interaction of style-size combinations, line width, and leading (spacing between lines), the choice of print for any particular material requires task specific investigation.
Prescription Label Readability
151
Despite these differences in research results, there are some published guidelines for legibility for geriatric individuals based on data collected with younger individuals (Ralph, 1982). Considering the well-documented, agerelated declines in visual abilities among older adults, however, it is unclear that these recommendations would be applicable for developing print guidelines for older adults. Furthermore, evidence suggests that task specific analyses are necessary to ensure the proper selection of print characteristics (Vanderplas & Vanderplas, 1980). The present research was designed to assess the effects of age, font type, size, and weight on the readability of prescription medication labels. It was hypothesized that the print characteristics investigated will affect reading performance and preference and that these effects will differ for individuals of different age groups.
EXPERIMENT 1 Method
Subjects. The subjects were 19 younger adults [9 males (mean age = 22.12, SD = 1.93) and 10 females (mean age = 28.5, SD = 6.93)] and 20 older adults, over the age of 65 [10 males (mean age = 69.8, SD = 5.94) and 10 females (mean age = 72.3, SD = 5.53)]. The older volunteers were recruited from a learning institute for elders within a university setting. Younger volunteers were recruited from undergraduate psychology classes. All subjects were prescreened for reading ability, cognitive functioning, and near visual acuity. To participate, subjects had to be reading at a minimum of an eighth-grade level, their scores on the Digit Symbol test of the WAIS-R had to fall within the normal range for their age group, and those subjects with low vision were required to wear their corrective lenses during the experiment. Design. The study was a 2 (age) x 2 (gender) x 3 (font) x 3 (size) x 2 (weight) mixed-model design. The between-subject factors were age (young, old) and gender (male, female). The within-subject factors were font (Courier, Century Schoolbook, Helvetica), size (9 point, 12 point, 14 point), and weight (Bold, Roman). Material. The materials used were 72 standard size medication bottles (20 dram), 72 hospital pharmacy labels, a demographic questionnaire, a reading abilities test, the Digit Symbol test from the WAIS-R, and a Titmus Vision Tester. The selection of print types used was based on a review of the literature, as well as a survey of fonts used in major Central Florida pharmacies (Courier, 9 point, Roman). Courier and Century Schoolbook are serif fonts,
152
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while Helvetica is a sans serif font. Century Schoolbook and Helvetica are proportional fonts, whereas Courier is a nonproportional font. The factorial combinations of font, size, and weight resulted in 18 label conditions. These conditions were then reproduced using four different sets of label information (LI). T h e LI sets were p r o d u c e d by the random assignment of the following pieces of information four times: (1) name of a physician, (2) name of a medication, (3) instructions, and (4) n u m b e r of refills. The end product of this process was four sets of 18 labeled medication bottles (see Table I). All labels were equated for content of information. Procedure. Subjects were first asked to complete the demographic questionnaire, a reading abilities test, and the Digit Symbol test. Next, each subject's near visual acuity was assessed. Each subject was then instructed to read the information on 18 labeled prescription bottles, one at a time, as quickly and accurately as possible. The order of presentation of the 18 bottles was randomized for each subject to reduce order effects. Before starting the experimental portion of the study, subjects were allowed to practice the procedure with three medication bottles. Subsequently, subjects were instructed to pick up a medication bottle and read the label information aloud. Time to read was measured in 0:01 of a second using a stopwatch. Subject accuracy was also recorded. After reading all the labels, subjects were instructed to look at each label again and to judge the print on a 7-point scale according to (1) ease of reading (very easy-very difficult), (2) clearness of type (very sharp-not at all sharp), and (3) appropriateness of size (too small-too large). Table 1. Examples of Font Type, Weight, and Size Point size Font
9
12
14
Bold Courier Century Schoolbook Helvetica
Refill
Refill
Refill
Refill
Refill"
Refill Refill
Refill
Refill Roman
Courier Century Schoolbook Helvetica
Refill b
Refill
Refill
Refill
Refill
Refill
Refill
Refill Refill
aRecommended font, size, and weight combination for use on bottles and flat labels. bprint type used by major Central Florida pharmacies.
Prescription Label Readability
153
Results
Reading Speed. A 2 x 2 x 3 x 3 x 2 mixed-model analysis of variance was performed on the reading speed data and indicated significant main effects for four independent variables: age, font, weight, and size (see Table II). Older adults were significantly slower than younger adults, and Roman weight was significantly slower to read than Bold. Range tests of the main effect of font indicated that Courier required significantly longer time to read than Helvetica and Century Schoolbook (p's < .0001). Similar range tests for size indicated that 9-point print required significantly more time to read than 12- and 14-point print (p's < .00001). The analysis also revealed several significant interactions. However, only those interactions that include age effects are included in this report (see Table II). Tests of simple effects for the weight × age interaction indicated no effects of weight for older adults. The three-way interaction of font x size x age was broken down by age group. Tests of simple effects performed on the separate interactions indicated that older adults performed best with the 12-point Century Schoolbook print. This interaction also indicated that 9-point was particularly slow with the Courier font, especially for the older subjects. Performance Errors. A similar A N O V A of subject error data indicated significant main effects for the three independent variables of age, font, and size (see Table II). Older adults committed more errors than their younger counterparts. Range tests indicated that more errors were committed with the Courier font than with Century Schoolbook or Helvetica (p's < .01) and that more errors were committed with the 9-point size than with the 12- or 14-point size (p's < .05). The analysis also revealed significant age interactions of font × age, weight x age, and font × weight x age (see Table II). Tests of simple effects for the font × age interaction indicated that older adults committed more errors with the Courier font than with Century Schoolbook or Helvetica (p's < .01) and that older adults committed more errors than younger adults with the Courier font (p's < .001). Furthermore, the weight x age interaction showed that older adults committed more errors with the Bold than the Roman print (p's < .01) and more errors with the Bold print than younger adults (p's < .001). The nature of this interaction indicated no effects of weight for younger adults. The three-way interaction was broken down by age group to form two font × weight interactions. Tests of simple effects of these interactions indicated that older adults committed more errors with the Courier Bold print than with the Courier Roman (p's < .001) and that older adults, when
2,68 1,34 2,68 1,34 2,68 2,70 2,70 2,68 2,68
Font (F) Weight (W) Size (S) W x A W x S x A Size (S) F x W x A
Font (F) Size (S)
Reading ease
Size
*p
