The most common types of measures used to collect data about health and health be- haviors are instruments in which the participant provides a direct report of knowledge, attitudes, intentions, perceptions, or behaviors. These self-report measures include in- terviews, questionnaires, journals, diaries, scales and indexes; these are described in the following sections.
Interviews
Broadly defined, an interview is a special situation in which a participant is asked a ques- tion or a series of questions about a phenomenon by an individual trained in inter- viewing techniques. Interviews can range from relatively unstructured events to highly structured ones. Using an unstructured format, the interviewer asks one or more broad, open-ended questions about a phenomenon, to which the respondent is expected to provide detailed responses. For example, the interviewer might say, “Tell me how you stay healthy.” The interviewer then guides the respondent through an in-depth dis- cussion of the phenomenon by using probing, reflecting, and reinforcing comments.
Interviewers generally use the unstructured interview approach in exploratory and qual- itative research. In these situations, the researcher approaches the interview without predetermined ideas about the phenomenon. An unstructured interview is an at- tempt to determine what the phenomenon means to the participant in the study, rather than an attempt to validate what is already known. During the interview, the interviewer takes notes and may use a tape recorder to record the entire discussion. Later, the re- searcher transcribes the audiotapes and analyzes the transcripts employing a variety of techniques grounded in qualitative research methodology.
In contrast to the unstructured interview format, a highly structured interview is one in which the interviewer reads items verbatim from an interview script and records the respondent’s answers. In this type of interview, interviewers generally rely on closed-ended items, in which the respondent is asked to choose from a list of response options. They ask few if any open-ended questions. If they do include open-ended questions, the requested response is generally short (for example, Question: What is your favorite type of exercise? Response: Running). In health behavioral studies, researchers commonly collect data using the structured-interview format.
A semistructured interview is one that combines elements of both unstructured and highly structured interviews. Researchers include both open-ended and closed-ended
questions. Thus, in one approach, an interviewer might ask a respondent to answer a se- ries of closed-ended items and then to clarify selected responses by providing more de- tail. In another approach, an interviewer might begin the discussion by asking an open-ended question and then probe for more specific details using closed-ended ques- tions. Researchers use the semistructured interview when they want to explore a range of opinions, perceptions, and attitudes about a specific topic. Although the research can be exploratory, the researcher is usually interested in a specific aspect of the phenomenon.
Focus group scripts are excellent examples of the semistructured interview. Re- searchers convene focus groups for a variety of reasons, including generating items for questionnaires, gathering feasibility data during the pilot phase of a study, or obtaining perspectives on the results of a study during the interpretation phase. The purpose of the focus group is fairly specific and the researchers generally have a good understand- ing of the type of information they want to collect. However, they lack a full apprecia- tion of the range of opinions and ideas that people hold about the topic.
Questionnaires
Questionnaire is a general term used to describe instruments that consist of items an- swered directly by the respondent. The usual format for the questionnaire is paper- and-pencil, and the items on the questionnaire are predominantly closed-ended questions. Recent advances in computer technology now allow respondents to com- plete questionnaires using a computer. A survey is a special type of questionnaire designed to address specific research questions. Most surveys consist primarily of closed-ended items. In practice, we often use the terms questionnaire and survey inter- changeably. Sometimes the manner of administration of the questionnaire determines
Open- and Closed-Ended Questions
Responses to closed-ended questions (also called forced-choice responses) are predetermined, so that the respondent selects the best answer for him or her from a list of two or more answer choices. Open-ended questions allow re- spondents to compose their own responses. Responses to closed-ended ques- tions are easier to code for statistical analysis, but the responses lack detail.
Open-ended questions generate variability in responses, more detail, and more precise responses. However, analysis of data is more complex.
the term used to refer to it. For example, we refer to a questionnaire administered in a face-to-face meeting by a trained interviewer as a structured interview. We generally call a questionnaire administered over the telephone by a trained interviewer a tele- phone survey, and one mailed to a respondent’s home a mail survey.
A questionnaire or survey can contain a single type of item or a variety of types.
Examples of types of items that a questionnaire or survey might include follow.
A simple item is one in which the respondent chooses between two options, such as yes/no, male/female, and married/not married. For example:
What is your sex?
Male Female
Another simple type of item requires a short written response.
What is your age?
How many fruits did you eat yesterday?
Another example of a simple item is one in which participants rate their attitudes, their opinions, or their health using a response scale. Response scales can consist of two options (these are called dichotomous) or more.
Medicare should pay for prescription medications for all Americans over 65 years of age.
Agree Disagree
How would you rate your health?
Excellent Good Average Poor Very poor
Researchers employ multiple-choice and true/false items primarily to assess knowl- edge. Examples are
HIV is caused by a bacterium.
True False
The variable marital status is usually measured on what type of scale?
A. Nominal B. Ordinal C. Interval D. Ratio
Checklists, such as the following, are often used to obtain information on medical histories.
Which of the following health conditions have you ever had? (Check ✓all that apply.)
Anemia Asthma Diabetes Ear infection Heart disease High blood pressure Seizures
Sinus infection
A questionnaire can also include other types of items, such as those that require the ranking of items or those that require short responses. The type of item, the length of the questionnaire, and the questionnaire format depend on a variety of factors, in- cluding the expertise of the researcher, the type of respondent (including age and education), and the mode of delivery (telephone, mail, face-to-face, or computer as- sessment). (Chapter Seven discusses item development.)
Journals and Diaries
Journals and diaries are used to collect data about events, feelings, emotions, and be- liefs. Journaling is an activity in which a respondent writes detailed notes about thoughts and experiences. When used in health behavior research, journaling is re- lated to a health event, perhaps one’s experiences related to the diagnosis and treat- ment of breast cancer. The information obtained from a journal is treated much like data collected through unstructured interviews. Researchers read the journal entries and categorize feelings, attitudes, behaviors, and events according to general themes.
Journaling tends to generate a large amount of information that requires considerable time to process, code, and analyze. Because of these drawbacks, journaling is not a common method of measuring health-related variables.
A diary is similar to a journal in that the researcher asks the respondent to record events and emotional or cognitive elements of those events. The research diary, how- ever, tends to be more structured than the journal. Researchers might ask participants to record what they eat during a twenty-four-hour period as a means of measuring food or nutrient intake. Researchers might also ask respondents to use a calendar to record seizures, side effects of medications, symptoms associated with illness or treat- ments, headaches, arrhythmias, exercise, or physical activity.
Response Scales
The response scale is one of the more common approaches for collecting data on opin- ions, perceptions, and attitudes. A response scale asks respondents to select, on a scale, a point that most closely represents their position from low to high or from negative to positive. The first use of a response scale has been attributed to Hipparchus, who is noted to have used a six-point scale in 150 B.C. to assess the brightness of stars (Lodge, 1981).
Response scales represent graduated increments of agreement, frequency, or evaluation (Spector, 1992). Using a scale that assesses agreement, respondents indicate how much they agree with a particular statement: for frequency, respondents indicate how often they perform a particular behavior; for the evaluative scale, respondents rate items according to how positive or negative they feel about them.
FIGURE 2.1. RESPONSE FORMAT FROM A WORKSHEET COMPLETED BY A FIRST-GRADE STUDENT.
a lot some a little not much
a lot some a little not much
I liked this story
I liked the way I worked today
FIGURE 2.2. WONG-BAKER FACES PAIN RATING SCALE.
Source: Wong, D. L., M. Hockenberry-Eaton, D. Wilson, M. L. Winkelstein, and P. Schwartz, Wong’s Essentials of Pediatric Nursing, 6th ed., St. Louis, 2001, p. 1301. Copyrighted by Mosby, Inc.
Reprinted by permission.
Faces Pain Rating Scale
No hurt Hurts
little bit
Hurts little more
Hurts even more
Hurts whole lot
Hurts worst
0 1 2 3 4 5
Response scales come in a variety of formats, some of which are depicted in Figures 2.1 and 2.2 and Exhibit 2.1. Depending on the type of response scale, the respondent might circle a number, letter, word, or figure; insert a check mark (✓) or X, or draw a line to mark a respondent’s position on a continuum.
Scaling Methods
Scaling is a process whereby researchers use a set of items to measure behaviors, attitudes, or feelings. The most common reason for scaling is to obtain a single score that represents a person’s overall attitude, belief, or behavior about a given situa- tion or object (Trochim, 2001). Several forms of scaling exist; there are specific rules for developing and using each scale. In Chapter Seven, we present procedures for the development of scales. Here, we describe five types: the visual analog scale (VAS), the Thurstone scale, the Likert scale, the Guttman scale, and the semantic differen- tial rating scale (SD). The VAS and the Likert scales are the most commonly used scales in health behavior research, followed by the SD. Although the Thurstone and Guttman scales are presented here, they are rarely used in health behavior research.
However, because these scales are frequently cited, students should be familiar with them and appreciate the reasons they are rarely selected as methods for data collection.
Visual Analog Scale. The visual analog scale is a type of graphic rating scale. The concept underlying the VAS dates back to Freyd, who in 1923 described a similar pro- cedure for use in assessing personality traits (Freyd, 1923). During the past thirty years, the VAS has gained popularity in health behavior research and evaluation
because of its simplicity. Researchers have used the VAS to measure a variety of health phenomena, including pain, nausea, fatigue, and anxiety.
The most basic type of VAS consists of a straight horizontal or vertical line, 100 mm long. At each end, the scale developer places a perpendicular line, to clearly mark the starting and ending points of the line. Terms depicting extreme positions anchor the end points. For example, a VAS to measure pain might have anchor phrases of no pain and pain as bad as it could be. A VAS to measure anxiety could have the anchor phrases not nervous at all and the most nervous I have ever been (Cline, Herman, et al., 1992). The re- spondent marks the point on the line that corresponds most closely to his or her position on the phenomenon being assessed at that moment. Each respondent’s numeric score is calculated by measuring the distance from one end of the line to the respondent’s mark on the line. The length of this distance is considered to be the respondent’s score.
The 100 mm line has special significance because it allows the researcher to mea- sure the amount of the phenomenon on a continuous scale from 0 (none of the phe- nomenon) to 100 (maximum amount). Traditional response scales requiring a selection
EXHIBIT 2.1. EXAMPLES OF RESPONSE FORMATS.
Place an X on the line that most closely reflects the extent to which you agree or disagree with each statement.
The instructor seemed knowledgeable about the subject matter.
Agree Disagree
Circle the word that most closely reflects the extent to which you agree or disagree with each statement.
The instructor seemed knowledgeable about the subject matter.
Strongly agree Agree Disagree Strongly disagree
Circle the number that corresponds most closely to the extent of your agreement with each statement.
The instructor seemed knowledgeable about the subject matter.
Strongly agree Agree Disagree Strongly disagree
1 2 3 4
Circle the number that corresponds most closely to the extent of your agreement with each statement.
1 = Strongly disagree 10 = Strongly agree
The instructor seemed knowledgeable about the subject matter.
1 2 3 4 5 6 7 8 9 10
of one of several responses (for example, agree or disagree) fall in the category of ordi- nal scales. Although it is possible to rank scores from low to high, one cannot assume that people with the same score have exactly the same amount of the attribute or that there is an equal amount of the attribute between each pair of points on the scale. The VAS more closely approximates the continuous scale (Price, McGrath, et al., 1983).
A number of variants of the simple form of the VAS exist (Paul-Dauphin, Guillemin, et al., 1999). In addition to the simple line with anchors, a VAS might in- clude a perpendicular line at the midpoint or perpendicular lines at equal intervals along the line (graduated VAS). These gradations might include numbers (10, 20, 30, and so on) or verbal descriptors (not at all, a little, moderately, a lot) or both. Another type of VAS eliminates the line and includes only numbers, with verbal anchors at the ends. To make the task appealing to respondents, some researchers use familiar de- vices such as ladders or thermometers to depict the attribute and the end points.
Thurstone Scale. In the 1920s, L. L. Thurstone (Thurstone & Chave, 1929) made a major breakthrough in the measurement of attitudes. Thurstone believed that ask- ing people about their preferences would be more interesting and perhaps more rel- evant for the study of psychology than sensory-stimuli testing (for example, just noticeable differences in weight). His work led to the development of three scaling methods: equal-appearing intervals, paired comparisons, and successive intervals. In each approach, respondents are asked to select from a set of items those that they endorse. Each item has a preassigned weight, and researchers add the preassigned weights for the items that are endorsed to obtain a total score. The three approaches differ in the ways in which the weights are determined for the items. Here we will describe the methods for determining the weights for the equal-appearing interval ap- proach to attitude measurement.
This process begins with the development of a large set of items (about 100) re- lated to the attitude to be assessed. Judges who are experts in the area are asked to sort the items into eleven piles from lowest to highest according to the strength or desir- ability of the attitude. After the judges are satisfied with their rankings, the researcher evaluates each item individually. The values of the ranks given to the items by the judges are placed in order from high to low. The middle (median) rank value is selected as the weight for each item. The final step is to select a representative set of items from
FIGURE 2.3. GENERAL FORM OF A VISUAL ANALOG SCALE.
None Maximum
the total set. This process is carried out by rank-ordering the items according to their median weights and selecting items that represent the full range of scores, with equal intervals between successive items. An example will help clarify the process.
A researcher who plans to develop a Thurstone scale to assess attitudes toward people with epilepsy begins by writing items that express positive, negative, and neu- tral attitudes about people with epilepsy. These items might include such statements as, “People with epilepsy should not drive,” and, “People with epilepsy can do any- thing anyone else can do.” After writing and editing 100 items, the researcher gives the items to experts on epilepsy and asks them to sort the items into eleven piles from most negative to most positive attitudes. To make the task easier, the researcher puts each item on a separate card. After the judges are satisfied with the rankings they have assigned to all the items, the researcher evaluates items individually. Suppose that the rank values of the judges for the item “People with epilepsy can do anything they want” are as follows: 6, 6, 7, 7, 8, 8, 8, 9, 9, 9. The median value is 8, and this value is selected as the weight for the item. To select the final set of items for this scale, the items are put in order (piles) by their median values, and ten items are selected (Ex- hibit 2.2). These ten items have values ranging from 1 to 10, with one point between successive items. When using the scale, a person who agrees with the statement
“People with epilepsy can do anything anyone else can do” will receive a score of 8; a person who agrees with the statement “People with epilepsy should not drive” will re- ceive a score of 3. Total scores are found by adding together the rank value of each item to which the respondent agrees. On this scale, higher scores correspond to more positive attitudes toward people with epilepsy.
EXHIBIT 2.2. EXAMPLE OF A THURSTONE SCALE, USING HYPOTHETICAL ITEMS AND WEIGHTS
FOR AN EPILEPSY ATTITUDE SCALE.
Item (weight) Agree Disagree
1. People with epilepsy can do anything they want. (8) 1 2 2. People with epilepsy should not drive. (3) 1 2 3. People with epilepsy should not get married. (4) 1 2 4. People with epilepsy should not be around heavy
machinery. (6) 1 2
5. People with epilepsy are mentally ill. (1) 1 2 6. People with epilepsy should not have children. (2) 1 2 7. People with epilepsy can hold important positions. (9) 1 2 8. People with epilepsy cannot hold a job. (5) 1 2 9. People with epilepsy should be treated like anyone else. (10) 1 2 10. People with epilepsy make a valuable contribution to
society. (7) 1 2
Note: Numbers in parentheses correspond to the rank value of the item.
Likert Scale. Rensis Likert (Likert, 1932), among others, liked Thurstone’s idea of measuring preferences but believed that the method of weighting items was time- consuming and cumbersome. For his dissertation, Likert developed a simple approach to constructing attitudinal scales. The Likert scale, also called a summated rating scale, is now the most widely used scale for measuring behaviors, attitudes, and feelings. The Likert scale builds on the concept of the one-item response scale. Rather than using one item to measure the totality of an attribute, the scale uses several items to assess an attribute. Respondents rate each item individually, and the responses are added to obtain a total score.
The Rosenberg Self-Esteem Scale (Rosenberg, 1965, 1989) is a good example of a Likert scale. Rosenberg developed this scale in 1965 to measure self-esteem among adolescents and adults (Table 2.1). The participant is first asked to respond to each item by circling the number that best represents his or her level of agreement. To obtain a total score on the Rosenberg Self-Esteem Scale, researchers add the responses to each item. Note that items numbered 3, 5, 8, 9, and 10 are negatively worded. That is, strong agreement with these items indicates a low level of self-esteem. By con- trast, items numbered 1, 2, 4, 6, and 7 are positively worded, so that strong agreement with them is consistent with a high level of self-esteem. To compute a total score for the scale, the negatively worded items must first be reverse-scored. To reverse-score items, researchers code responses to the items in an order opposite to their numeri- cal order. For example, with the Rosenberg Self-Esteem Scale, a response of 1 to a negatively worded item is coded 4; a response of 2 is coded 3; a response of 3 is coded
Negatively Worded Items
Negatively worded items on a scale are those items to which strong agreement would indicate low levels of the concept. A negatively worded item on a hap- piness scale might be “I do not feel cheerful most of the time.” A high level of agreement with this item would indicate a low level of happiness. Another neg- atively worded item might be “I feel sad,” because a high level of agreement with this item also would indicate a low level of happiness. Note that the first item, “I do not feel cheerful most of the time,” includes the word not, but the second item, “I feel sad,” does not. The term negatively worded item refers not to the grammatical negativity of the statement, but to the way the response to the item corresponds to the concept. If depression were the concept under con- sideration, both of these items would be considered positively worded, and the item “I feel happy” would be considered a negatively worded item.