TABLE 1.
Methods of studies included in systematic review
| Reference | Study design (method) | Number of participants (age) | Medication, actual or hypothetical situation | Inclusion criteria (location) | Risk of bias |
|---|---|---|---|---|---|
| Al Juffali et al 2014 26 | Cross‐sectional study, factorial design. Between groups, two factors: presentation format (verbal/numerical), side‐effect (dry eyes/loss of hair) (paper questionnaire) | 141 (mean age 23 y, range 21 to 25 y) | Acne medication (roaccutane), actual situation | Patients who were newly prescribed Roaccutane for the first time at three selected hospitals (Saudi Arabia) | 15 |
| Andrykowski and Gregg 1992 27 | Prospective cohort study (paper questionnaire, medical records) | 65 (mean age 59.6 y, SD = 11.7) | Chemotherapy, actual situation | Patients at a community‐based cancer centre who were at least 18 y old, and who received an initial course of intravenous cytotoxic chemotherapy as either an inpatient or outpatient, but were scheduled to receive their remaining chemotherapy infusions as an outpatient (not reported) | 10 |
| Berry et al 2002 28 ; Berry et al 2002 29 | Study 1: Cross‐sectional study, factorial design. Between groups, two factors: side‐effect severity (mild/severe), response presentation format (percentage/frequency). Within groups, one factor: probability term (very common/common/uncommon/rare/very rare) (paper questionnaire) | 268 (range 18 to 55 y) | Medication for throat or ear infections (counterbalanced across condition), hypothetical situation | Undergraduate and post‐graduate students who were members of the psychology department research panel (University of Reading, UK) | 11 |
| Study 2: Cross‐sectional study, factorial design. Between groups, one factor: presentation format (verbal/numerical) (paper questionnaire) | 112 (range 18 to 70 y) | Medication for throat or ear infections, hypothetical situation | Volunteers from the general population (Reading, UK) | 10 | |
| Berry et al 2002 30 | Study 1: Cross‐sectional study, factorial design. Between groups, four factors: disease severity (mild/severe), side‐effect severity (mild/severe), side‐effect likelihood (likely/unlikely), side‐effect number (many/few) (paper questionnaire) | 976 (range 18 to 70 y) | Medication for one of two diseases, hypothetical situation | Volunteers from the general population (Reading, UK) | 10 |
| Study 2: Cross‐sectional study, factorial design. Between groups, three factors: disease severity (mild/severe), side‐effect severity (mild/severe), benefit statement (no statement/positive benefit/unknown benefit) (paper questionnaire) | 592 (range 18 to 70 y) | 9 | |||
| Study 3: Cross‐sectional study, factorial design. Between groups, three factors: disease severity (mild/severe), side‐effect severity (mild/severe), benefit statement (no statement/prevention statement/alleviation statement) (paper questionnaire) | 515 (range 18 to 70 y) | 9 | |||
| Berry et al 2003 31 | Study 1 and 2: Cross‐sectional study, factorial design. Between groups, one factor: personalization (personalized/not‐personalized) (paper questionnaire) | Study 1: 95 (range 18 to 50 y) | Medication for pneumonia or another severe illness (not named), hypothetical situation | Volunteers from the general population (Reading, UK) | 11 |
| Study 2: 100 (range 18 to 60 y) | Medication for subacute thyroiditis, hypothetical situation | 11 | |||
| Berry et al 2003 32 ; Berry et al 2002 29 | Study 1: Cross‐sectional study, factorial design. Between groups, two factors: age (18‐40,41‐60,61‐80), presentation format (verbal/numerical) (paper questionnaire) | 120 (18 to 40 y, n = 40; 41 to 60 y, n = 40; 61 to 80 y, n = 40) | Medication for throat or ear infection, hypothetical situation | Volunteers from the general population (Reading, UK) | 10 |
| Study 2: Cross‐sectional study, factorial design. Between groups, three factors: presentation format (verbal/numerical), frequency (common/rare), side‐effect severity (severe/ mild) (paper questionnaire) | 360 (18 to 75 y) | 10 | |||
| Berry 2004 33 | Cross‐sectional study, factorial design. Between groups, one factor: parental status (parent/not parent). Within groups, one factor: patient type (adult/child) (paper questionnaire) | 136 (range 20 to 50 y) | Medication for throat or ear infection, hypothetical situation | Volunteers from the general population (Reading, UK) | 10 |
| Berry et al 2004 34 | Study 1: Cross‐sectional study, factorial design. Between groups, one factor: side‐effect severity (mild/severe). Within groups, one factor: probability term (very common/common/uncommon/rare/very rare). Compared with results from Berry et al 2002 28 (paper questionnaire) | 56 (mean age 37 y, range 28 to 55 y) | New short course antibiotic, hypothetical situation | Doctors attending a rheumatology conference (UK) | 11 |
| Study 2: Cross‐sectional study, factorial design. Between groups, two factors: sample population (student/ doctor), side‐effect severity (mild/severe). Within groups, one factor: probability term (high >1%/moderate 0.1%–1%/low 0.01%–0.1%/very low 0.001%–0.0001%/minimal 0.0001%–0.00001%/ negligible <0.00001%) (paper questionnaire) | 55 medical doctors (mean age 36 y, range 28 to 48 y), 160 students (mean age 29 y, range 19 to 50 y) |
Doctors: new short course antibiotic, hypothetical situation Students: medication for throat or ear infection, hypothetical situation |
Doctors: Doctors attending a rheumatology conference Students: undergraduate and post‐graduate students at the University of Reading (UK) |
10 | |
| Berry et al 2004 35 | Cross‐sectional study, factorial design. Between groups, one factor: presentation format (verbal/numerical) (paper questionnaire) | 188 (range 18 to 70 y) | Ibuprofen, hypothetical situation | Volunteers from the general population (Reading, UK) | 13 |
| Berry et al 2006 36 | Cross‐sectional study, factorial design. Between groups, two factors: risk increase format (relative risk, absolute risk, number needed to harm), baseline information (included, not included) (paper questionnaire) | 268 (mean age 29 y, SD = 12.54, range 18 to 45 y) | Oral contraceptive pill, mixed—presented as hypothetical situation but 30% were currently taking pill and 37% had done so in the past | Female volunteers from the general population (Reading, UK) | 12 |
| Bersellini and Berry 2007 37 | Study 2: Cross‐sectional study, factorial design. Between groups, two factors: effectiveness statement (included/not included), rationale statement (included/not included) (paper questionnaire) | 292 (range 18 to 75 y) | Short course antibiotic for a throat infection, hypothetical situation | Volunteers from the University of Reading (UK) | 10 |
| Blalock et al 2016 38 | Randomized trial, factorial design. Between groups, two factors: side‐effect probability format (low side‐effect probability, numeric/ high side‐effect probability, numeric/non‐numeric), benefit condition (low benefit probability, risk with and without treatment numeric/high benefit probability, risk with and without treatment numeric/low benefit probability, risk difference numeric/high benefit probability, risk difference numeric/non‐numeric) (online questionnaire) | 999 (mean age 33.9 y (SD = 11.1) | Medication to lower cholesterol, hypothetical situation | People from Amazon Mechanical Turk (remote) | 12 |
| Colagiuri et al 2008 39 | Randomized control trial (interview, questionnaire) | 671 (average age 53 y, range 25 to 90 y) | Chemotherapy, actual situation | Patients aged 18 y or over with any cancer diagnosis and were about to receive their first chemotherapy treatment (USA) | 14 |
| Cox 2019 40 | Study 2: Cross‐sectional study, factorial design. Between groups, two factors: adjective (rare/common), adverb (very/no adverb) (online questionnaire) |
712 (25 to 29 y, 16.5%; 30 to 34 y, 17.4%; 35 to 39 y, 17.4%; 40 to 44 y, 16.2%; 45 to 49 y, 15.8%; and 50 to 55 y, 16.7%) |
Pain reliever, hypothetical situation | People from Survey Sampling International (remote) | 9 |
| Davis 2007 41 | Cross‐sectional study (online questionnaire) | 669 (age 18 to 34 y, 36.5%; age 35 to 64 y, 61.9%) | Three prescription drugs (allergy, cholesterol, insomnia), hypothetical situation | Sample of 3200 individuals from Syracuse University's Study Response Project (USA) | 10 |
| Fischer and Jungermann 1996 42 | Study 1: Cross‐sectional study, factorial design. Between groups, one factor: presentation format (verbal/verbal and base rate). Within‐group: severity of side‐effect (mild/severe) (paper questionnaire) | 82 (not reported) | Drug (disease not specified), hypothetical situation | Students from the Department of Psychology of the Technical University Berlin | 8 |
| Franic and Pathak 2000 43 | Cross‐sectionals study, mixed factorial design. Between groups, one factor: phrasing (second‐/third‐person description of scenarios). Within‐group: three factors: frequency of side‐effects (rarely/occasionally/frequently), severity of side‐effect (mild/severe), context (general/specific/very specific) (postal questionnaire) | 74 (second person phrased surveys: mean age 28 y, range 19 to 41 y; third person phrased surveys: mean age 30, range 21 to 40 y) |
General context: ‘new medication’, hypothetical situation Specific context: ‘new birth control pill, taken once daily at the same time each day’, hypothetical situation Very specific context: ‘new pain relief medication for period cramps (menstrual pain) which started at the earliest onset of pain and is taken every six hours when needed for pain relief. Patients typically require the pain killer for approximately three to five days’, hypothetical situation |
Random sample of 400 (/842) female patients of child‐bearing age from the Women's Clinic at the Ohio State University Medical Center in Columbus (Ohio, USA) | 13 |
| Gardner et al 2011 44 | Cross‐sectional study, amalgamation of data from four separate studies including Knapp et al 2009 45 and Knapp et al 2010 46 (two studies not published), factorial designs (online questionnaires) | 591 (mean age 46.5 y, SD = 10.8, range 15 to 66 y) | Tamoxifen (endocrine therapy for cancer), mixed—presented as hypothetical situation but 78% had cancer (n = 461), 44.3% were taking tamoxifen or had previously taken tamoxifen (n = 262) | People navigating to the Tamoxifen page on the www.cancerhelp.org.uk website (remote) | 11 |
| Goetsch et al 1991 47 | Prospective cohort study: baseline, one month follow‐up, three month follow‐up (postal questionnaires) | 38, n = 19 taking contraceptives for the first time, n = 17 using oral contraceptives for at least 6 months (range 18 to 24 y) | Oral contraceptives, actual situation | Unmarried females recruited from contraceptive education programmes (West Virginia University and Western Michigan University, USA) | 7 |
| Heisig et al 2015 48 | Study 1 and 2: Cross‐sectional study using two time points (pre‐/post‐information), factorial design. Between groups, two factors: treatment benefit framing (no emphasis/emphasis), presentation (personalized/standard business‐like interaction) (not reported) | Study 1: 60 (mean age 50 y) | Adjuvant endocrine treatment for breast cancer, hypothetical situation | Healthy women older than 18 y who were fluent in German, without a history of mamma carcinoma, any other cancer diagnoses within the last 5 y, personal experience with endocrine treatment, or presence of a serious physical illness (not reported) | 13 |
| Study 2: 64 (mean age 50 y) | Chemotherapy for breast cancer, hypothetical situation | Healthy women older than 18 y who were fluent in German, without a history of mamma carcinoma, any other cancer diagnoses within the last 5 y, personal experience with chemotherapy, or presence of a serious physical illness (not reported) | 13 | ||
| Heisig et al 2016 49 | Cross‐sectional study (not reported) | 165 (mean age 58 y, SD = 9.59) | Adjuvant endocrine therapy for treatment of breast cancer, actual situation | Women with a diagnosis of hormone receptor‐positive breast cancer with an indication for adjuvant endocrine therapy, with no progress of disease or relapse, diagnosis of other current carcinoma, having received neo‐adjuvant chemotherapy, having a severe acute psychiatric disorder or a physical comorbidity substantially influencing quality of life, and starting endocrine therapy before baseline assessment or having pre‐experiences with endocrine therapy (four breast cancer centres in Marburg and Hamburg, Germany) | 14 |
| Hickok et al 2001 50 | Prospective cohort study (paper questionnaire) | 63 (mean age 52.5 y, range 33 to 83 y) | Chemotherapy without concurrent radiotherapy, actual situation | Patients at the University of Rochester Cancer Center, two local affiliated hospitals and a private oncology practice in Rochester, NY, between December 1994 and September 1997 who were being treated with an initial course of chemotherapy, were not receiving radiotherapy concurrently, did not have any primary malignancy or metastatic disease affecting the brain, and were at least 19 y of age (New York, USA) | 10 |
| Hofman et al 2004 51 | Prospective longitudinal study (semi‐structured clinical interview, self‐report questionnaires, medical records) | 938 (mean age 58 y, range 24 to 88 y) | Chemotherapy (n = 616, 66%) or radiation therapy (n = 538, 57%) for treatment of breast, lung, prostate, haematologic, gastrointestinal, or head and neck cancer (~25% patients received chemotherapy and radiation therapy), actual situation | Clinical outpatients at private medical oncology practices who were grantees of the National Cancer Institute's Community Clinical Oncology Program (CCOP) and were members of the University of Rochester Cancer Center (URCC) CCOP Research Base. Participants were newly diagnosed with cancer whose treatment plan included chemotherapy or radiation who had not had previous chemotherapy or radiation therapy (USA) | 13 |
| Hofman et al 2004 52 | Cross‐sectional study (questionnaire) | 1015 (not reported) | Chemotherapy and radiation treatment, actual situation | Cancer patients from 17 Community Clinical Oncology Program (CCOP) institutions affiliated with the University of Rochester CCOP research base USA) | 4 |
| Hubal and Day 2006 53 | Cross‐sectional study. Frequency experiment. Within groups, one factor: side‐effect frequency terms (38 terms used). Severity experiment. Within groups, one factor: severity term (19 terms used) (questionnaire) | 222. Numeric task, n = 206; visual task, n = 16 (not reported) | Side‐effects (medication not reported), hypothetical situation | Undergraduate students from Duke University (USA) | 7 |
| Jacobsen et al 1993 54 , a | Prospective cohort study (in person and telephone interviews) | 53 (mean age 49 y, range 29 to 78 y) | Adjuvant chemotherapy treatment for breast cancer, actual situation | Patients at a cancer centre who were aged 18 y or over, had undergone mastectomy for breast carcinoma, had not previously received radiotherapy or cytotoxic chemotherapy and who were scheduled to receive their first six infusions of outpatient adjuvant chemotherapy (not reported) | 8 |
| Montgomery et al 1998 55 , a | Prospective cohort study (in person and telephone interviews) | 59 (mean age 48.8 y) | Adjuvant chemotherapy treatment for breast cancer (sixth infusion), actual situation | Women diagnosed with Stage I or II breast cancer who were at least 18 y of age, had undergone mastectomy, had completed standard nurse‐administered pre‐chemotherapy teaching and had not previously received radiotherapy or cytotoxic chemotherapy (not reported) | |
| Knapp et al 2001 56 | Cross‐sectional study, factorial design. Between groups, two factors: presentation format (verbal/numerical), frequency of side‐effect (very common/common/uncommon/rare) (paper questionnaire) | 155 (38% aged over 40 y) | Asthma, antibiotics, statins, actual situation | Adult attenders at a community pharmacy; a general practice asthma clinic and hospital cardiac rehabilitation clinic, who were on inhalers for asthma, antibiotics or a statin (not reported) | 7 |
| Knapp et al 2004 57 | Randomized controlled trial. Between groups, two factors: presentation format (verbal/numerical), side‐effect (constipation/pancreatitis) (paper questionnaire) | 120 (median age 63 y, range 35‐74 y) | Simvastatin or atorvastatin, actual situation | Adults attending cardiac rehabilitation clinics at two hospitals following a recent admission for coronary artery bypass surgery or myocardial infarction who were taking either simvastatin or atorvastatin (Leeds, UK) | 14 |
| Knapp et al 2009 58 | Cross‐sectional study, factorial design. Between groups, one factor: presentation format (verbal/percentage/frequency) (online questionnaire) | 148 (mean age 42.9 y, SD = 12.8, range 18 to 66 y) | Study 1: Taxol ® (chemotherapy treatment), mixed—presented as hypothetical situation but some participants had had side‐effects from Taxol ® before | People navigating to Taxol® page on the www.cancerhelp.org.uk website (remote) | 10 |
| Cross‐sectional study, factorial design. Between groups, one factor: presentation format (verbal/percentage/frequency) (online questionnaire). Within‐group, one factor: response format (percentage/frequency) (online questionnaire) | 137 (mean age 39.1 y, SD = 14.2, range 16 to 66 y) | Study 2: Ibuprofen, mixed—presented as hypothetical situation but some participants had had side‐effects from ibuprofen before | People navigating to a page on pain management on the www.cancerhelp.org.uk website (remote) | 10 | |
| Knapp et al 2009 45 | Cross‐sectional study, factorial design. Between groups, one factor: presentation format (verbal/frequency/combined) (online questionnaire) | 187 (mean age 42.8 y, SD = 12.9, range 15 to 66 y) | Tamoxifen (endocrine treatment for cancer), likely to be mixed, but presented as hypothetical situation (not reported if some participants were taking/had taken tamoxifen | People navigating to the Tamoxifen page on the www.cancerhelp.org.uk website (remote) | 14 |
| Knapp et al 2010 46 | Cross‐sectional study, factorial design. Between groups, two factors: type of numerical description (absolute frequency/frequency band), presentation format (numerical/combined) (online questionnaire) | 134 (mean age 47.6 y, SD = 9.1) | Tamoxifen (endocrine therapy for cancer), mixed—presented as hypothetical situation but 48.6% currently taking tamoxifen, 4.5% previously taken tamoxifen, 20.2% about to take tamoxifen | People navigating to the www.cancerhelp.org.uk website (remote) | 10 |
| Knapp et al 2013 59 | Randomized controlled trial. Three presentation formats: frequency, percentage, combined (online questionnaire) | 129 (mean age 49.2 y, SD = 9.6, range 15 to 66 y) | Tamoxifen (endocrine therapy for cancer), mixed—presented as hypothetical situation but 51.9% currently taking tamoxifen, 11.6% previously taken tamoxifen, 20.2% about to take tamoxifen | People navigating to the Tamoxifen page on the www.cancerhelp.org.uk website (remote) | 16 |
| Knapp et al 2016 60 | Cross‐sectional study, factorial design. Between group, two factors: presentation format (numerical/verbal and numerical), verbal qualifier (may affect/will affect) (online questionnaire) | 339 (mean 48.5 y, range 16 to 80 y) | Paclitaxel (Taxol; chemotherapy treatment), mixed—presented as hypothetical situation but 7.7% currently taking Taxol, 6.1% previously taken Taxol, 3.9% about to take Taxol | People navigating to the webpage on drugs commonly used in the treatment of cancer or to the webpage on Taxol on the www.cancerhelp.org.uk website (remote) | 16 |
| Lynch and Berry 2007 61 | Study 1: Cross‐sectional study, factorial design. Within groups, one factor: medicine type (prescribed/over‐the‐counter/herbal) (paper questionnaire) | 77 (range 18 to 70 y) | Medication for persistent stomach indigestion, hypothetical situation | Volunteers from the general population (UK) | 13 |
| Mapes 1979 62 | Cross‐sectional study. Between groups, one factor: drug (beta‐blocker/antihistamine and chloramphenicol/neomycin sulphate) (postal questionnaire) | 64 (not reported) | Beta‐blocker, antihistamine, chloramphenicol, neomycin sulphate, hypothetical situation | Two groups of male unrestricted principals in general practice who were physicians (East Anglia, UK) | 4 |
| Mazur and Merz 1994 63 | Cross‐sectional study, factorial design. Between groups, two factors: scale length (long/short), severity of complication (death from anaesthesia/severe pneumonia) (online questionnaire) | 210 (not reported) | Operation, hypothetical situation | Patients in a general medical clinic seen consecutively for their medical problems by the physician investigator in a university‐based Department of Veterans Affairs Medical Center (not reported) | 8 |
| Montgomery and Bovbjerg 2003 64 | Prospective cohort study (paper questionnaire) | 80 (mean age 6.9 y) | Adjuvant chemotherapy treatment for breast cancer, actual situation | Patients at an outpatient breast cancer centre who were at least 18 y of age; had never previously received radiation therapy or cytotoxic chemotherapy; had been diagnosed with Stage I or II breast cancer; were status post‐radical, modified radical, or segmental mastectomy; and were scheduled to receive outpatient adjuvant chemotherapy every 21 d (not reported) | 11 |
| Montgomery and Bovbjerg 2004 65 | Prospective cohort study (paper questionnaire) | 63 (mean age 48.7, SD = 12.4) | Surgery for breast cancer (lumpectomy, excisional breast biopsy), actual situation | Patients scheduled for breast cancer surgery (not reported) | 9 |
| Moraes and Dal Pizzol 2018 66 | Randomized controlled trial, three presentation format: verbal descriptor and percentage range, percentage range, absolute percentage (paper questionnaire) | 389 (18 to 34 y, n = 32; 35 to 59 y, n = 152; ≥60 y, n = 205) | Medicine for gastrointestinal problems, hypothetical situation | People aged over 18 with normal cognitive and communication skills who went to a ‘training pharmacy’ (enables internship training for pharmacy students) located in a university (Brazil) | 18 |
| O’Connor et al 1996 67 ; O’Connor et al 1997 68 | Prospective cohort study (self‐report questionnaire and telephone interview) | 292 (positive framing condition: mean age 53 y, SD = 13; negative framing condition, mean age 52 y, SD = 14) | Influenza vaccine, mixed—presented as hypothetical situation but uptake of the vaccine was measured as one of the study outcomes | Patients from outpatient respiratory and cardiac clinics at two teaching hospitals and one private group respiratory practice who were recommended for influenza immunization, that is were aged 65 y or over, or under 65 with chronic pulmonary or cardiac disorders severe enough to require regular medical follow‐up or hospital care (Ottawa, Canada) | 17 |
| Ohnishi et al 2002 69 | Cross‐sectional study (paper questionnaire) |
168 patients (mean age 51 y, SD = 18.1, range 17 to 83 y) 156 physicians (mean age 36 y, SD = 8.2 range 24 to 76 y) |
Cold medicine, anti‐cancer drug, hypothetical situation | Japanese patients aged 16 or over at the General Medicine Clinic at Kyoto University Hospital with no moderate or severe distress or cognitive problems and physicians from the Japanese General Medicine Research Network (Japan) | 11 |
| Pan et al 2018 70 | Prospective cohort study (semi‐structured interview, clinical assessment, medical records, questionnaire) | 116 (mean age 55.4 y, SD = 9.97) | Adjuvant endocrine treatment for breast cancer, actual situation | Women with hormone receptor‐positive breast cancer or ductal carcinoma in situ indicated for adjuvant endocrine therapy | 11 |
| Parrella et al 2013 71 | Cross‐sectional study (computer aided telephone interviews) | 469 (age 18 to 34 y, n = 89; age 35 to 44 y, n = 220; age 45 y and over, n = 160) | Immunizations, hypothetical situation | Adults who were randomly selected from electronic residential telephone listings who identified as a parent or legal guardian of children aged 18 y or younger (rural and metropolitan South Australia) | 17 |
| Roscoe et al 2000 72 | Prospective cohort study (questionnaire) | Study 1: 29 (mean age 60.5 y, SD = 11.4, range 34 to 79 y) | Chemotherapy for ovarian cancer, actual situation | Women with ovarian cancer who were being treated with either cisplatin or carboplatin as inpatients at the University of Rochester Cancer Center who were chemotherapy naïve (New York, USA) | 12 |
| Study 2: 81 (mean age 54.1 y, SD = 11.8, range 33 to 83) | Chemotherapy for a variety of cancer diagnoses, actual situation | Patients with a variety of cancer diagnoses being treated with a variety of chemotherapy drugs at the University of Rochester Cancer Center, two locally affiliated hospitals, and a private oncology practice in Rochester who were chemotherapy naïve (New York, USA) | 12 | ||
| Schnur et al 2007 73 | Cross‐sectional study (paper questionnaire) | 418 (mean age 48.3 y, SD = 13.7, range 19 to 83 y) | Breast conserving surgery, actual situation | Female patients scheduled for breast conserving surgery by two surgeons who were at least 18 y old and who were not currently in treatment for a psychiatric illness (New York, USA) | 12 |
| Schwartz et al 2009 74 | Randomized controlled trial—symptom drug box (telephone interview, postal questionnaire) | Control group, n = 109 (mean age 53 y, interquartile range 43 to 63 y). Drug box group, n = 122 (mean age 55 y, interquartile range 47 to 61 y). | Drug for heartburn (proton‐pump inhibitor and histamine‐2 blocker), hypothetical situation | Volunteers who were aged 35 to 70 y from a random‐digit dial sample of 3000 (USA) | 8 |
| Randomized controlled trial—prevention drug box (telephone interview, postal questionnaire) | Control group, n = 108 (mean age 55 y, interquartile range 47 to 62 y). Drug box group, n = 111 (mean age 54 y, interquartile range 47 to 60 y). | Statins and clopidogrel for secondary cardiovascular prevention, hypothetical situation | Volunteers who were aged 35 to 70 y from a random‐digit dial sample of 3000 (USA) | 8 | |
| Shedden‐Mora et al 2017 75 | Prospective cohort study, randomized controlled trial (not reported) | 196 (not reported) | Adjuvant endocrine therapy for breast cancer, actual situation | Women with breast cancer (not reported) | 2 |
| Shelke et al 2008 76 | Randomized trial, two groups: standard education materials (control), standard education materials plus supplement about effectiveness of medication at controlling nausea and vomiting (intervention) (paper questionnaire) | 358 (control group, mean age 57.8 y, SD = 13.4, range 28.3 to 91.4 y. Intervention group, mean age 57.4 y, SD = 12.1, range 27.4 to 84.3 y) | Chemotherapy, actual situation | Chemotherapy‐naïve cancer patients scheduled to receive their first treatment at eighteen private medical oncology practice groups that were grantees of the National Cancer Institute's Community Clinical Oncology Program (CCOP) and were members of the University of Rochester Cancer Center CCOP Research Base (USA) | 13 |
| Sullivan et al 2015 77 | Benefit design study. Cross‐sectional study, factorial design. Between groups, two factors: benefit (low/high), presentation format (numeric/numeric and qualitative/absolute difference and qualitative/full) and no‐information and qualitative only (online questionnaire) | 2537 (18 to 40 y, n = 594; 41 to 52 y, n = 639; 53 to 64 y, n = 683; 65 + y, n = 621) | Bone loss from fictitious prescription drug for heartburn, hypothetical situation | Online panellists from the 2007 National Health Interview Survey data with self‐reported symptoms of heartburn or acid reflux in the last 3 mo, who were aged 18 or over, and were not working for a pharmaceutical, advertising, or market research company; and not being a health‐care professional (remote) | 15 |
| Risk design study. Cross‐sectional study, factorial design. Between groups, two factors: risk (low/high), presentation format (numeric/numeric and qualitative/absolute difference and qualitative/full) and no‐information and qualitative only (online questionnaire) | 2531 (18 to 40 y, n = 617; 41 to 52 y, n = 649; 53 to 64 y, n = 643; 65 + y, n = 622) | 15 | |||
| Sutherland et al 1991 78 | Test‐retest study, factorial design. Between groups, two factors: mode of delivery (paper/online), interviewer (1/2) (paper and online questionnaire) | 100 (n = 35 per group; interviewer 1, computer administration mean age 54.0 y, SD = 13.3; interviewer 1, paper administration mean age 52.3 y, SD = 13.4; interviewer 2, computer administration mean age 58.7 y, SD = 14.4; interviewer 2, paper administration mean age 57.3 y, SD = 11.6) | Blood transfusions, hypothetical situation | Out‐patients with an established diagnosis of cancer at the Princess Margaret Hospital Lodge (Ontario, Canada) | 8 |
| Tan et al 2005 79 | Cross‐sectional study (paper questionnaire), factorial design. Between groups, one group: presentation format (probability/frequency) (paper questionnaire) | Graduate students, n = 38. Health‐care professionals, n = 47. (Mean age, probability format—33.8 y, frequency format—34.2 y) | Influenza vaccine, hypothetical situation | Graduate students attending a biostatistics lecture given by the first author. Group of health‐care professionals attending a workshop given by second author (Singapore) | 12 |
| Taylor et al 2007 80 | Cross‐sectional study (postal questionnaire) | 1202 (mean age 52.7 y, SD = 6.4, range 18 to 97 y) | Non‐prescription medications, mixed—presented as hypothetical situation, but 42.3% had previously bought a non‐prescription medication at a convenience store, 91.6% had previously bought a non‐prescription medication at a pharmacy | Random sample of adults (Saskatoon, Saskatchewan, Canada) | 8 |
| Thorens et al 2008 81 | Cross‐sectional study (face‐to‐face interview) | 100 (age 19 to 39 y, n = 58; age 40 and above, n = 42; range 19 to 65 y) | Psychopharmacotherapy, actual situation | Patients in an inpatient ward of the public psychiatric hospital, with a minimum two day stay and with partial remission of acute behavioural or psychotic symptoms (Geneva, Switzerland) | 15 |
| Wallace 1985 82 | Study 1: Prospective cohort study (face‐to‐face interview) | 118 (not reported) | Post‐surgical pain, actual situation | Female adults undergoing laparoscopic surgery for sterilization or infertility investigation admitted to a gynaecology ward (not reported) | 5 |
| Study 2: Prospective cohort study (face‐to‐face interview) | 63 (not reported) | 5 | |||
| Walmsley et al 1992 83 | Cross‐sectional study (face‐to‐face interview) | 101 (over 55 y) | Post‐surgical pain, actual situation | Patients scheduled for elective surgery; cardiac patients were excluded (not reported) | 10 |
| Webster et al 2017 84 , b | Cross‐sectional study (online questionnaire) | 1003 (median age 41.0 y, inter‐quartile range 22.0) | Unnamed drug, hypothetical situation | Random sample of adults aged between 18 and 65 y (England) | 19 |
| Webster et al 2017 85 , b | Cross‐sectional study, factorial design. Between groups, one group: severity of side‐effects (mild/severe). Between groups: presentation format (online questionnaire) | ||||
| Whitford and Olver 2012 86 | Prospective cohort study (paper questionnaire) | 45 (mean age 55.4 y, SD = 13.7, range 22 to 79 y) | Chemotherapy, actual situation | Chemotherapy‐naïve patients in a medical oncology department who had a cancer diagnosis and a prognosis of more than six months (Royal Adelaide Hospital Cancer Center, Australia) | |
| Woloshin et al 1994 87 | Cross‐sectional study, factorial design. Within‐group, one factor: severity of side‐effect (minor/major) (paper questionnaire) | 307 (mean age 36.2 y) | Medication for hypertension, vaccination, surgery, antibiotic, hypothetical situation | Patients seen in a university‐based family practice who were aged 18 y or over, or parents of patients aged younger than 18 y who were not presenting for general physical examination (not reported) | 13 |
| Woloshin and Schwartz 2011 88 | Parallel‐group randomized trial, five groups: natural frequency, variable frequency, percentage, percentage plus natural frequency, percentage plus variable frequency (online questionnaire) | 2944 (mean age 47 y, range 18 to 93 y) | Drugs for heartburn and cholesterol, hypothetical situations | Adult volunteers randomly selected from a professional survey firm's research panel of about 30,000 households (USA) | |
| Zachariae et al 2007 89 | Prospective cohort study (paper questionnaire diary) | 125 (range 18 to 70 y) | Chemotherapy, actual situation | Women receiving standard adjuvant chemotherapy after surgery for breast cancer aged between 18 and 70 y who could read and write Danish (Aarhus University Hospital, Denmark) | 8 |
a
These results are from the same group of participants.
b
These results are from the same group of participants.