Background
Method
Search strategy
Inclusion and exclusion criteria
Study selection, data extraction, and quality assessment
Statistical method
Results
Cohort, participant, and article characteristics
Sample | Reference | Study Name | Wave 1 Sample Size | Wave 1 Mean Age | Overall Retention Rate | No. Waves | Study Duration (years) | No. Retention Strategies |
---|---|---|---|---|---|---|---|---|
Clinical cohort studies | ||||||||
Adolescent and adult non-injecting heroin users | [32] | Project Brown | 300 | 16–40 | 98% | 2 | 1.00 | 9 |
Adolescent/young adult cancer patients | [33] | Resilience in Adolescents and Young Adults with Cancer Study | 52 | 17.6 | 35% | 3 | 1.50 | 4 |
Adolescent/Young Adult mobile young injection drug users | [34] | 101 | 22 | 48% | 6 | 2.00 | 9 | |
Adolescents and young adults with Type 1 Diabetes | [35] | Young Adult Diabetes Assessment (YADA) | 204 | 17–18 | 97% | 3 | 5.00 | 18 |
Adult asthmatic pregnant women | [36] | Syracuse AUDIT (Assessment of Urban Dwellings for Indoor Toxics) | 103 | 25.4 | 86% | 5 | 1.00 | 9 |
Adult cannabis users | [37] | 193 | 32 | 84% | 90 | 0.25 | 3 | |
Adult entitlement claimants from the Accident Compensation Corporation | [38] | Prospective Outcomes of Injury Study (POIS) | 2856 | 18–64 | 79% | 4 | 2.00 | 4 |
Adult major trauma patients | [39] | Victorian State Trauma Registry | 1102 | 40 | 70% | 2 | 0.50 | 3 |
Adult myocardial infarction survivors | [40] | Western New York Acute Myocardial Infarction (MI) Study | 884 | 54 | 90% | 4 | 7.00 | 2 |
Adult parents of overweight children with low-income | [41] | 37 | 20–50+ | 46% | 26 | 1.00 | 14 | |
Adult Puerto Rican/Mexicans with a mental health diagnosis | [42] | 68 | 18–50 | 59% | 3 | 5.00 | 20 | |
Adult smokers and non-smoker comparisons | [43] | International Tobacco Control (ITC) China Survey | 6001 | 18–55+ | 68% | 3 | 3.00 | 7 |
Adult spinal surgery patients | [44] | Danish spine surgery registry (Danespine) | 506 | 58.94 | 100% | 3 | 1.00 | 1 |
Adult survivors of ARDS | [45] | Toronto Acute Respiratory Distress Syndrome (ARDS) Study | 109 | – | 86% | 3 | 5.00 | 18 |
Adult survivors of SARS | [45] | Toronto Severe acute respiratory syndrome (SARS) Study | 117 | – | 91% | 2 | 2.00 | 17 |
Adults with diabetes | [46] | Living with Diabetes Study | 3951 | 61.4 | 81% | 3 | 3.00 | 15 |
Adult women at-risk of cardiovascular events | [47] | PREDICT Study | 1110 | 21+ | 90% | 9 | 2.00 | 12 |
Adult women at-risk of HIV infection | [48] | 411 | 21 | 94% | 2 | 1.00 | 4 | |
Adult women breast cancer survivors | [49] | 121 | 59.7 | 96% | 2 | 1.00 | 3 | |
Adult women with HIV/AIDS | [50] | Instituto de Pesquisa Clínica Evandro Chagas (IPEC) Cohort of Women Living with HIV/ AIDS followed up in Fundação Oswaldo Cruz (FIOCRUZ) Rio de Janeiro | 225 | 32 | 56% | 3 | 3.00 | 2 |
Adults at first-episode psychosis | [51] | 71 | 18–60 | 70% | 3 | 5.00 | 1 | |
Adults at-risk for HIV infection | [52] | 2191 | 18–49 | 77% | 2 | 1.00 | 4 | |
Adults at-risk of problem gambling plus comparison group | [53] | Quinte Longitudinal Study | 4121 | 46.1 | 94% | 5 | 5.00 | 1 |
Adults who self-harm | [54] | 150 | 28.4 | 95% | 3 | 6.00 | 4 | |
Adults who use urinary catheters | [55] | 33 | 43 | 100% | 4 | 0.50 | 2 | |
Adults with acute transient ischemic attack or stroke | [56] | Oxford Vascular Study | 1236 | 75.2 | 98% | 7 | 10.00 | 3 |
Adults with Alzheimers Disease | [57] | REAL.FR study | 686 | 77.9 | 59% | 2 | 2.00 | 3 |
Adults with Alzheimers Disease (AD) and their carers | [58] | 40 | 78 | 81% | 5 | 1.00 | 16 | |
Adults with Alzheimers Disease or Mild Cognitive Impairment and comparison | [59] | Australian Imaging, Biomarkers and Lifestyle Flagship Study of Ageing (AIBL) | 1112 | 69.7 | 90% | 2 | 1.50 | 3 |
Adults with aneurysmal subarachnoid hemorrhage (aSAH) | [60] | Family Caregiver study | 59 | 52 | 83% | 4 | 1.00 | 5 |
Adults with back pain | [61] | 250 | 30–59 | 68% | 14 | 7.00 | 3 | |
Adults with primary malignant brain tumour (PMBT) and their caregivers | [60] | 20-Hete Study | 496 | 53.12 | 90% | 3 | 1.00 | 3 |
Adults with primary Sjögren’s syndrome | [62] | 222 | 52.5 | 70% | 2 | 7.60 | 2 | |
Adults with schizophrenia and comparison group | [63] | 56 | 21 | 89% | 2 | 2.00 | 1 | |
Adults with Severe Traumatic Brain Injury | [64] | PariS-TBI study | 504 | 42 | 60% | 2 | 4.00 | 6 |
Adults with temporomandibular disorders | [65] | Orofacial Pain: Prospective Evaluation and Risk Assessment (OPPERA) Study | 3263 | 31 | 84% | 11 | 2.80 | 5 |
Adults with traumatic brain injury | [66] | Tasmanian Neurotrauma Register (TNTR) | 947 | 36.1 | 19% | 7 | 3.00 | 5 |
Adults with Traumatic Brain Injury | [67] | 77 | 67.1 | 57% | 3 | 0.50 | 1 | |
Adult burn victims | [68] | Burns Registry of Australia and New Zealand | 463 | 41.8 | 21% | 5 | 2.00 | 4 |
Caregivers of adult cancer patients | [69] | 206 | 57 | 85% | 3 | 1.10 | 1 | |
Child twins and their siblings | [70] | Australian Twin ADHD Project (ATAP) | 1938 | 4–12 | 43% | 3 | 9.00 | 3 |
Children at-risk of HIV infection | [71] | AIDS-ill families study | 3515 | 13.5 | 97% | 2 | 1.00 | 9 |
Children at-risk of thyroid cancer and comparison group | [72] | 600 | 11 | 88% | 2 | 8.00 | 9 | |
Children exposed to Cocaine/opiate and comparison | [73] | Maternal Lifestyle Study (MLS) | 13,888 | 0.1 | 76% | 5 | 15.00 | 16 |
Children perinatally infected with HIV and comparison | [74] | IMPAACT P1055 Psychiatric Co-Morbidity Study | 582 | 12.4 | 81% | 2 | 2.00 | 3 |
Children who were former child soldiers | [75] | 260 | 10–17 | 69% | 3 | 6.00 | 3 | |
Children with ADHD and a sibling for comparison | [26] | International Multicenter ADHD Genetics (IMAGE) study | 459 | 11.4 | 76% | 2 | 6.00 | 1 |
Children with ADHD and comparisons | [76] | Berkeley Girls with ADHD Longitudinal Study (BGALS) | 228 | 9.6 | 95% | 3 | 10.00 | 2 |
Female adolescent/young adult survivors of a mass campus shooting | [77] | 812 | 19 | 81% | 7 | 2.50 | 1 | |
Infants at-risk of developing diabetes | [78] | The Environmental Determinants of Diabetets in the Young (TEDDY) study | 4138 | 0.4 | 74% | 3 | 1.00 | 1 |
Male sex workers | [79] | 50 | 17–26+ | 34% | 2 | 0.50 | 4 | |
Men who have Sex with Men | [25] | Bangkok Men who have Sex with Men Cohort Study (BMCS) | 1744 | 26 | 90% | 10 | 3.00 | 3 |
Men who have Sex with Men | [80] | 2607 | 22.7 | 22% | 2 | 0.25 | 2 | |
Men who have Sex with Men | [81] | 710 | 18–54 | 74% | 2 | 1.00 | 5 | |
Men who have Sex with Men | [82] | 1003 | 28 | 70% | 8 | 2.60 | 1 | |
Men who have Sex with Men | [83] | 511 | 29 | 55% | 3 | 0.75 | 5 | |
Men who have Sex with Men | [84] | 278 | 32 | 16% | 3 | 1.00 | 5 | |
Men who have Sex with Men | [85] | 327 | 30.8 | 92% | 3 | 1.00 | 1 | |
Population at-risk for HIV infection | [86] | 1000 | 13–49 | 77% | 5 | 2.50 | 3 | |
Non-clinical cohort studies | ||||||||
Adolescent mother-child dyads | [87] | 97 | 14–20 | 38% | 3 | 4.00 | 9 | |
Adolescent population | [88] | Danish Youth Cohort | 12,498 | 13.4 | 25% | 3 | 2.00 | 1 |
Adolescent population | [89] | Dating It Safe | 964 | 16.1 | 86% | 2 | 1.00 | 1 |
Adolescent population | [90] | Healthy Teens Longitudinal Study | 611 | 14.8 | 66% | 7 | 6.00 | 1 |
Adolescent population | [91] | International Youth Development Study (IYDS) | 1858 | 13 | 98% | 3 | 2.00 | 4 |
Adolescent population | [92] | TRacking Adolescents’ Individual Lives Survey (TRAILS) | 2773 | 11.1 | 79% | 4 | 8.00 | 1 |
Adolescent population | [93] | Youth Asset Study (YAS) | 1117 | 12–17 | 97% | 5 | 4.00 | 32 |
Adolescent population | [94] | 1535 | 14.9 | 57% | 2 | 1.00 | 1 | |
Adolescent population | [95] | 497 | 13.03 | 86% | 6 | 6.00 | 1 | |
Adolescent/Young adult twins | [96] | Minnesota Twin Family Study (MTFS) | 1252 | 17 | 93% | 4 | 12.00 | 1 |
Adult African American population | [97] | Religion and Health in African Americans (RHIAA) study | 2803 | 54.86 | 40% | 2 | 2.50 | 16 |
Adult African American women | [98] | Study of Environment, Lifestyle and Fibroids (SELF) | 1696 | 23–34 | 87% | 2 | 1.67 | 3 |
Adult Alaska Native and American Indian population | [99] | Education and Research Towards Health (EARTH) study | 3828 | 18–55+ | 88% | 2 | 1.50 | 18 |
Adult low income mothers | [100] | Welfare Client Longitudinal Study (WCLS) | 498 | 18–35+ | 89% | 2 | 1.00 | 11 |
Adult male population | [101] | Florey Adelaide Male Ageing Study (FAMAS) | 1195 | 55 | 96% | 2 | 1.00 | 14 |
Adult mother-child dyads | [102] | 4318 | 0.2 | 84% | 5 | 1.00 | 3 | |
Adult mother-child dyads | [103] | 365 | 13.7 | 64% | 2 | 1.00 | 4 | |
Adult officeworkers | [104] | 53 | 42 | 100% | 26 | 1.00 | 1 | |
Adult online panel members | [105] | ATTEMPT Cohort | 2009 | 47.9 | 52% | 5 | 1.00 | 3 |
Adult online panel members | [106] | 202 | 33.8 | 47% | 3 | 0.00 | 1 | |
Adult population | [107] | Baltimore Epidemiologic Catchment Area Follow-up | 3481 | 18–65+ | 53% | 3 | 23.00 | 1 |
Adult population | [108] | Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) study | 3722 | 30–64 | 79% | 3 | 4.00 | 12 |
Adult population | [109] | Heart Strategies Concentrating on Risk Evaluation (Heart SCORE) study | 1841 | 59.1 | 84% | 5 | 4.00 | 11 |
Adult population | [110] | Helsinki Aging Study (HAS) | 170 | 80 | 42% | 2 | 5.00 | 3 |
Adult population | [111] | Knee Clinical Assessment Study (CAS(K)) | 819 | 50–80+ | 95% | 2 | 1.50 | 3 |
Adult population | [112] | Longitudinal Assessment of Women (LAW) | 511 | 64.7 | 96% | 5 | 5.00 | 16 |
Adult population | [113] | Midlife in the United States (MIDUS) | 7108 | 25–74 | 75% | 2 | 10.00 | 4 |
Adult population | [114] | MRC National Survey of Health and Development (NSHD) | 3163 | 60–64 | 84% | 2 | 9.00 | 2 |
Adult population | [115] | Netherlands Mental Health Survey and Incidence Study (NEMESIS-2) | 18–64 | 18+ | 80% | 2 | 3.00 | 9 |
Adult population | [116] | Netherlands Study of Depression and Anxiety (NESDA) | 2981 | 39.9 | 87% | 2 | 2.00 | 10 |
Adult population | [117] | New Zealand Attitudes and Values Study | 6518 | 48 | 62% | 4 | 3.00 | 12 |
Adult population | [118] | NutriNet-Santé Cohort Study | 15,000 | 18+ | 44% | 2 | 2.00 | 8 |
Adult population | [119] | People’s Republic of China-United States of America (PRC-USA) Collaborative Study of Cardiovascular and Cardiopulmonary Epidemiology | 1739 | 57.7 | 94% | 3 | 5.00 | 1 |
Adult population | [120] | Quinte Longitudinal Study (QLS) | 4121 | 18–65+ | 94% | 5 | 5.00 | 1 |
Adult population | [121] | Study of health in Pomerania (SHIP) | 6267 | 20–79 | 84% | 2 | 5.00 | 10 |
Adult population | [122] | Study of Use of Products and Exposure-Related Behavior (SUPERB) | 481 | 36 | 47% | 9 | 3.00 | 3 |
Adult population | [123] | 700 | 48.8 | 71% | 4 | 2.00 | 2 | |
Adult pregnant women | [124] | Drakenstein Child Health Study (DCHS) | 585 | 26.6 | 90% | 2 | 1.33 | 6 |
Adult pregnant women | [125] | G-GrippeNet (GGNET) Project | 153 | 34 | 78% | 10 | 0.20 | 2 |
Adult pregnant women | [126] | Maternal Anxiety in Relation to Infant Development (MARI) Study | 306 | 28 | 90% | 7 | 2.00 | 2 |
Adult pregnant women | [127] | Mater-University Study of Pregnancy (MUSP) | 6753 | 24.3 | 88% | 6 | 27.00 | 5 |
Adult pregnant women | [128] | Pregnancy, Infection, and Nutrition Study | 262 | 30 | 70% | 2 | 2.00 | 5 |
Adult pregnant women | [129] | 118 | 31.6 | 72% | 4 | 1.00 | 1 | |
Adult pregnant women | [130] | 40,333 | 30.3 | 65% | 2 | 0.75 | 1 | |
Adult pregnant women | [131] | 1040 | 18–34+ | 71% | 3 | 1.10 | 1 | |
Adult premenopausal women | [132] | Uterine Fibroid Study (UFS) | 1141 | 35–49 | 85% | 3 | 8.00 | 5 |
Adult South Asians living in US | [133] | Mediators of Atherosclerosis in South Asians Living in America (MASALA) study | 906 | 40–84 | 48% | 2 | 0.75 | 6 |
Adult veterans | [134] | 1319 | 33 | 79% | 2 | 1.00 | 4 | |
Adult women | [135] | Australian Longitudinal Study on Women’s Health | 14,247 | 18–23 | 77% | 4 | 4.00 | 8 |
Adult women | [136] | Australian Longitudinal Study on Women’s Health | 40,395 | 18–75 | 80% | 2 | 6.00 | 5 |
Adult women | [137] | Manitoba Breast Screening Program | 47,637 | 50–68 | 80% | 2 | 2.50 | 5 |
Adult women | [138] | 1435 | 40–50 | 72% | 3 | 3.00 | 13 | |
Adult women | [139] | 48,125 | 38 | 91% | 2 | 12.00 | 5 | |
Adult women hoping to become pregnant | [140] | 30 | 29.4 | 43% | 4 | 1.50 | 2 | |
Adult/Young Adult Probationers | [141] | 199 | 17–35 | 52% | 5 | 15.00 | 7 | |
Birth cohort | [142] | Australian Aboriginal Birth Cohort study | 686 | 0 | 72% | 3 | 18.00 | 31 |
Birth cohort | [143] | Birth to Twenty (BT20) birth cohort | 3273 | 0 | 70% | 19 | 16.00 | 16 |
Birth cohort | [144] | Danish National Birth Cohort | 61,895 | 0 | 63% | 2 | 7.00 | 1 |
Birth cohort | [145] | ECAGE Project (Study of Food Intake and Eating Behavior of Pregnant Women) | 462 | 0 | 94% | 3 | 0.65 | 2 |
Birth cohort | [146] | Environments for Healthy Living (EHL) | 3368 | 0 | 65% | 2 | 5.50 | 7 |
Birth cohort | [147] | Geographic research on wellbeing (GROW) study | 9256 | 7 | 33% | 2 | 7.00 | 9 |
Birth cohort | [148] | Growing up in New Zealand | 6846 | 0 | 95% | 2 | 0.75 | 23 |
Birth cohort | [149] | Japan Children’s Study (JCS) | 467 | 0.3 | 81% | 6 | 3.50 | 13 |
Birth cohort | [150] | Nascita e INFanzia gli Effetti dell’Ambiente (NINFEA) cohort | 7003 | 0 | 78% | 4 | 4.00 | 6 |
Birth cohort | [151] | 413 | 0 | 95% | 2 | 0.50 | 1 | |
Birth cohort | [152] | 1196 | 0 | 46% | 5 | 30.00 | 1 | |
Birth cohort of children from Lesbian parents | [153] | US National Longitudinal Lesbian Family Study (NLLFS) | 154 | 0 | 93% | 5 | 17.00 | 1 |
Child African-American population and their parents | [154] | 76 | 3.4 | 70% | 2 | 3.50 | 18 | |
Child monozygotic (MZ) and dizygotic (DZ) twins | [155] | University of Southern California Study of Risk Factors for Antisocial Behavior (USC RFAB) | 1569 | 9 | 59% | 5 | 8.00 | 10 |
Child population | [156] | Danish youth cohort Vestliv | 3054 | 14.5 | 64% | 3 | 6.00 | 1 |
Child population | [157] | Ho Chi Minh City Youth Cohort | 759 | 11.8 | 77% | 5 | 5.00 | 4 |
Child population | [158] | 405 | 11 | 91% | 4 | 4.00 | 17 | |
Indigenous adolescents | [159] | 671 | 11.3 | 79% | 8 | 8.00 | 7 | |
Mother-child dyads | [160] | Center for Oral Health Research in Appalachia 2 (COHRA2) Study | 744 | 28.4 | 79% | 2 | 2.50 | 1 |
Older adults | [161] | Cardiovascular Health Study (CHS) | 5888 | 73 | 46% | 2 | 7.00 | 2 |
Older adults | [162] | Chinese Longitudinal Healthy Longevity Survey (CLHLS) | 16,020 | 65+ | 56% | 3 | 2.00 | 1 |
Older adults | [163] | Longitudinal Aging Study Amsterdam (LASA) | 3107 | 70 | 32% | 6 | 17.00 | 6 |
Older adults | [164] | New England Centenarian Study (NECS) | 759 | 97+ | 86% | 2 | 3.50 | 1 |
Older adults | [165] | Newcastle 85+ Study | 854 | 85+ | 40% | 4 | 5.00 | 11 |
Older adults | [166] | Physiological Research to Improve Sleep and Memory Project | 78.2 | 70+ | 83% | 3 | 2.00 | 24 |
Older adults | [167] | UAB Study of Aging | 1000 | 65+ | 95% | 2 | 4.00 | 16 |
Population during political turmoil | [168] | 889 | 36 | 89% | 2 | 0.50 | 1 | |
Population during political turmoil | [169] | 1022 | 33.9 | 85% | 2 | 6.00 | 7 | |
Young adult women population | [170] | Chlamydia Incidence and Re-infection Rates Study (CIRIS) | 1116 | 21 | 79% | 3 | 1.00 | 13 |
Overall Mean (Std Dev) | 3459 (8979) | 24.7 (23.5) | 73.9% (20.1%) | 4.6 (8.0) | 4.5 (5.1) | 6.2 (6.2) |
Relationship between retention rate and study or participant characteristics
Relationship between retention rate and retention strategy types
Studies using strategy | Studies not using strategy | Absolute Difference |
P
| I2 | |||
---|---|---|---|---|---|---|---|
N
| Retention Rate (Lower CI - Upper CI) |
N
| Retention Rate (Lower CI - Upper CI) | ||||
Reducing barriers to participation (Any vs None) | 109 | 0.81 (0.77–0.84) | 34 | 0.71 (0.62–0.78) | 0.10 | 0.01* | 99.87% |
Adapt materials for mixed abilities (e.g., non-English speaking participants) | 4 | 0.74 (0.37–0.93) | 139 | 0.79 (0.75–0.82) | − 0.05 | 0.67 | 99.88% |
Adjust inclusion criteria | 1 | na | |||||
Adjust lab to be more home-like, less clinical | 2 | 0.81 (0.77–0.84) | 141 | 0.79 (0.75–0.82) | 0.02 | 0.84 | 99.89% |
Advisory group | 2 | 0.68 (0.58–0.77) | 141 | 0.79 (0.75–0.82) | − 0.11 | 0.56 | 99.89% |
Alternative method of data collection | 36 | 0.86 (0.78–0.92) | 107 | 0.76 (0.72–0.8) | 0.10 | 0.01** | 99.88% |
Anonymity for participants | 1 | na | |||||
Assistance with postage costs | 5 | 0.88 (0.73–0.95) | 138 | 0.79 (0.75–0.82) | 0.09 | 0.21 | 99.89% |
Assistance with transport/parking/directions | 12 | 0.8 (0.73–0.86) | 131 | 0.79 (0.75–0.82) | 0.01 | 0.72 | 99.88% |
Catering/refreshments | 10 | 0.87 (0.8–0.92) | 133 | 0.78 (0.74–0.82) | 0.09 | 0.13 | 99.88% |
Child care | 3 | 0.68 (0.51–0.82) | 140 | 0.79 (0.75–0.82) | − 0.11 | 0.36 | 99.89% |
Consistency in research staff | 11 | 0.87 (0.77–0.93) | 132 | 0.78 (0.74–0.82) | 0.09 | 0.09 | 99.88% |
Partial data collected from proxy/data linkage | 27 | 0.81 (0.73–0.86) | 116 | 0.79 (0.74–0.82) | 0.02 | 0.42 | 99.88% |
Adapt materials for different languages | 12 | 0.84 (0.72–0.92) | 131 | 0.78 (0.75–0.82) | 0.06 | 0.39 | 99.88% |
Extended data collection window | 7 | 0.74 (0.54–0.88) | 136 | 0.79 (0.75–0.82) | − 0.05 | 0.52 | 99.88% |
Flexibility from research team (e.g., hours called, scheduling) | 24 | 0.83 (0.76–0.89) | 119 | 0.78 (0.74–0.82) | 0.05 | 0.23 | 99.88% |
Focus group on survey design | 2 | 0.72 (0.7–0.75) | 141 | 0.79 (0.75–0.82) | −0.07 | 0.93 | 99.89% |
Hiring, training, and support of staff | 21 | 0.84 (0.77–0.9) | 122 | 0.78 (0.74–0.82) | 0.06 | 0.11 | 99.88% |
Matching staff to participants, e.g., by language spoken, nature of questions | 2 | 0.94 (0.91–0.96) | 141 | 0.79 (0.75–0.82) | 0.15 | 0.14 | 99.88% |
Minimising time between data collection points | 1 | na | |||||
Pilot testing | 4 | 0.81 (0.63–0.91) | 139 | 0.79 (0.75–0.82) | 0.02 | 0.93 | 99.89% |
Prioritising measures | 12 | 0.73 (0.6–0.82) | 131 | 0.8 (0.76–0.83) | −0.07 | 0.37 | 99.89% |
Recruiting for long-term retention | 10 | 0.83 (0.67–0.92) | 133 | 0.79 (0.75–0.82) | 0.04 | 0.50 | 99.87% |
Schedule two participants simultaneously - often family or friends | 2 | 0.76 (0.66–0.84) | 141 | 0.79 (0.75–0.82) | −0.03 | 0.92 | 99.89% |
Simple, efficient procedure | 1 | na | |||||
Site and home visits | 31 | 0.84 (0.78–0.88) | 112 | 0.77 (0.73–0.81) | 0.07 | 0.07 | 99.88% |
Skip waves | 15 | 0.84 (0.75–0.9) | 128 | 0.78 (0.74–0.82) | 0.06 | 0.25 | 99.88% |
Splitting data collection over multiple sessions | 2 | 0.79 (0.78–0.81) | 141 | 0.79 (0.75–0.82) | 0.00 | 0.90 | 99.89% |
Survey design (e.g., order of survey items) | 3 | 0.77 (0.52–0.91) | 140 | 0.79 (0.75–0.82) | −0.02 | 0.88 | 99.88% |
Toll-free project phone number | 5 | 0.75 (0.57–0.88) | 138 | 0.79 (0.75–0.82) | −0.04 | 0.75 | 99.89% |
Creating a project community (Any vs None) | 59 | 0.80 (0.75–0.85) | 84 | 0.78 (0.73–0.82) | 0.02 | 0.48 | 99.88% |
Advisory group | 2 | 0.68 (0.58–0.77) | 141 | 0.79 (0.75–0.82) | − 0.11 | 0.56 | 99.89% |
Branding | 14 | 0.79 (0.65–0.89) | 129 | 0.79 (0.75–0.82) | 0.00 | 0.99 | 99.88% |
Certificate of appreciation/completion | 2 | 0.83 (0.28–0.98) | 141 | 0.79 (0.75–0.82) | 0.04 | 0.82 | 99.88% |
Champion participants | 1 | na | |||||
Educating the community on research | 5 | 0.87 (0.7–0.95) | 138 | 0.79 (0.75–0.82) | 0.08 | 0.40 | 99.89% |
Emphasising benefits of study | 3 | 0.82 (0.7–0.9) | 140 | 0.79 (0.75–0.82) | 0.03 | 0.79 | 99.89% |
Events/opportunity to meet other participants | 9 | 0.69 (0.54–0.82) | 134 | 0.8 (0.76–0.83) | −0.11 | 0.23 | 99.88% |
Feedback report | 10 | 0.84 (0.73–0.91) | 133 | 0.79 (0.75–0.82) | 0.05 | 0.39 | 99.88% |
Gaining support of relevant institutions and organisations | 4 | 0.85 (0.71–0.93) | 139 | 0.79 (0.75–0.82) | 0.06 | 0.57 | 99.89% |
Gift/ freebies | 19 | 0.8 (0.67–0.88) | 124 | 0.79 (0.75–0.82) | 0.01 | 0.90 | 99.89% |
Hiring, training, and support of staff | 21 | 0.84 (0.77–0.9) | 122 | 0.78 (0.74–0.82) | 0.06 | 0.11 | 99.88% |
Letter from chief investigator | 1 | na | |||||
Media coverage | 3 | 0.7 (0.69–0.72) | 140 | 0.79 (0.75–0.82) | −0.09 | 0.82 | 99.89% |
Newsletter/e-newsletter | 24 | 0.83 (0.76–0.89) | 119 | 0.78 (0.74–0.82) | 0.05 | 0.23 | 99.88% |
Opportunity to participate in other research | 1 | na | |||||
Photo album | 2 | 0.72 (0.69–0.75) | 141 | 0.79 (0.75–0.82) | −0.07 | 0.75 | 99.89% |
Building rapport | 22 | 0.79 (0.69–0.86) | 121 | 0.79 (0.75–0.82) | 0.00 | 0.97 | 99.89% |
Sharing study results | 5 | 0.88 (0.66–0.97) | 138 | 0.79 (0.75–0.82) | 0.09 | 0.24 | 99.89% |
Social media | 2 | 0.89 (0.72–0.96) | 141 | 0.79 (0.75–0.82) | 0.10 | 0.39 | 99.89% |
Study membership card | 1 | na | |||||
Thank you, birthday, and holiday cards | 25 | 0.85 (0.79–0.9) | 118 | 0.78 (0.73–0.81) | 0.07 | 0.07 | 99.88% |
Time with chief investigator | 2 | 0.92 (0.8–0.97) | 141 | 0.79 (0.75–0.82) | 0.13 | 0.24 | 99.89% |
Website | 3 | 0.80 (0.47–0.94) | 140 | 0.79 (0.75–0.82) | 0.01 | 1.00 | 99.88% |
Follow-up/Reminder strategies (Any vs None) | 111 | 0.76 (0.72–0.80) | 32 | 0.86 (0.79–0.91) | −0.10 | 0.02* | 99.86% |
Follow-up brochure | 2 | 0.78 (0.74–0.81) | 141 | 0.79 (0.75–0.82) | − 0.01 | 0.97 | 99.89% |
Budgeting for multiple contact attempts | 1 | na | |||||
Extra incentive to complete all data collection points | 2 | 0.93 (0.77–0.98) | 141 | 0.79 (0.75–0.82) | 0.14 | 0.17 | 99.89% |
Gift/ freebies incentives (e.g., t-shirts, discount cards) | 18 | 0.8 (0.67–0.88) | 125 | 0.79 (0.75–0.82) | 0.01 | 0.90 | 99.89% |
Hiring, training, and support of staff | 21 | 0.84 (0.77–0.9) | 122 | 0.78 (0.74–0.82) | 0.06 | 0.11 | 99.88% |
Incentive (cash/vouchers) | 59 | 0.78 (0.72–0.82) | 84 | 0.8 (0.75–0.84) | −0.02 | 0.45 | 99.88% |
Incentive increasing value over time | 10 | 0.78 (0.62–0.88) | 133 | 0.79 (0.75–0.82) | − 0.01 | 0.81 | 99.88% |
Incentives raffles/competitions | 11 | 0.86 (0.71–0.94) | 132 | 0.78 (0.75–0.82) | 0.08 | 0.22 | 99.88% |
Increased incentive for hard-to-reach Pp | 6 | 0.68 (0.47–0.84) | 137 | 0.79 (0.76–0.83) | −0.11 | 0.24 | 99.88% |
Limiting number of calls etc. based on participants’ response | 1 | na | |||||
Medical assistance (e.g., diagnostic testing) | 27 | 0.74 (0.64–0.82) | 116 | 0.8 (0.76–0.84) | −0.06 | 0.17 | 99.88% |
Phone Follow-up | 11 | 0.80 (0.67–0.89) | 132 | 0.79 (0.75–0.82) | 0.01 | 0.90 | 99.88% |
Provide referrals, e.g., medical or legal | 9 | 0.85 (0.77–0.91) | 134 | 0.78 (0.75–0.82) | 0.07 | 0.26 | 99.89% |
Resend survey once | 6 | 0.77 (0.64–0.86) | 137 | 0.79 (0.75–0.82) | −0.02 | 0.79 | 99.88% |
Resend survey multiple times | 10 | 0.76 (0.64–0.84) | 133 | 0.79 (0.75–0.83) | −0.03 | 0.63 | 99.88% |
SMS follow-up | 1 | na | |||||
Website follow-up | 8 | 0.81 (0.62–0.91) | 135 | 0.79 (0.75–0.82) | 0.02 | 0.93 | 99.88% |
Email reminder | 13 | 0.73 (0.58–0.85) | 130 | 0.79 (0.76–0.83) | −0.06 | 0.31 | 99.88% |
Face-to-face reminder (e.g., home visit) | 7 | 0.85 (0.67–0.94) | 136 | 0.79 (0.75–0.82) | 0.06 | 0.33 | 99.89% |
Phone call reminder | 34 | 0.73 (0.63–0.8) | 109 | 0.81 (0.77–0.84) | −0.08 | 0.05* | 99.88% |
Postcard/letter reminder | 43 | 0.77 (0.7–0.83) | 100 | 0.80 (0.75–0.84) | −0.03 | 0.50 | 99.88% |
SMS reminder | 5 | 0.85 (0.8–0.9) | 138 | 0.79 (0.75–0.82) | 0.06 | 0.42 | 99.89% |
Reminders (unspecified) | 1 | na | |||||
Tracing strategies (Any vs None) | 53 | 0.80 (0.73–0.85) | 90 | 0.78 (0.74–0.83) | 0.02 | 0.62 | 99.88% |
Tracing via alternative contacts | 28 | 0.82 (0.75–0.87) | 115 | 0.78 (0.74–0.82) | 0.04 | 0.32 | 99.88% |
Case-review meetings | 1 | na | |||||
Tracing via change of address cards | 2 | 0.74 (0.43–0.91) | 141 | 0.79 (0.75–0.82) | −0.05 | 0.95 | 99.89% |
Tracing via email | 2 | 0.74 (0.43–0.92) | 141 | 0.79 (0.75–0.82) | −0.05 | 0.82 | 99.89% |
Extensive location tracking information, e.g., known ‘hangouts’ | 1 | na | |||||
Hiring, training, and support of staff | 21 | 0.84 (0.77–0.9) | 122 | 0.78 (0.74–0.82) | 0.06 | 0.11 | 99.88% |
Tracing via house visit | 1 | na | |||||
Tracing via incentive for staff members | 2 | 0.72 (0.67–0.76) | 141 | 0.79 (0.75–0.82) | −0.07 | 0.69 | 99.89% |
Tracing via incentive to update contact details | 3 | 0.86 (0.62–0.96) | 140 | 0.79 (0.75–0.82) | 0.07 | 0.43 | 99.88% |
Tracing via letter | 9 | 0.77 (0.51–0.91) | 134 | 0.79 (0.75–0.82) | −0.02 | 0.72 | 99.89% |
Tracing via locator form documentation* | 7 | 0.91 (0.79–0.97) | 136 | 0.78 (0.74–0.81) | 0.13 | 0.02* | 99.88% |
Tracing via phone call | 8 | 0.67 (0.51–0.8) | 135 | 0.8 (0.76–0.83) | −0.13 | 0.12 | 99.88% |
Tracing via private investigator | 1 | na | |||||
Tracing via SMS | 1 | na | |||||
Tracing via social media | 3 | 0.79 (0.39–0.95) | 140 | 0.79 (0.75–0.82) | 0.00 | 0.92 | 99.89% |
Tracing via tracing via public records | 20 | 0.82 (0.73–0.88) | 123 | 0.78 (0.74–0.82) | 0.04 | 0.37 | 99.88% |
Tracing via tracking database | 15 | 0.83 (0.73–0.9) | 128 | 0.78 (0.74–0.82) | 0.05 | 0.32 | 99.88% |
Tracing via update your details form | 4 | 0.9 (0.81–0.96) | 139 | 0.79 (0.75–0.82) | 0.11 | 0.15 | 99.89% |
Tracing via website | 2 | 0.80 (0.79–0.81) | 141 | 0.79 (0.75–0.82) | 0.01 | 0.99 | 99.89% |
Tracing via non-public records, e.g., apartment complex managers | 7 | 0.82 (0.66–0.92) | 136 | 0.79 (0.75–0.82) | 0.03 | 0.59 | 99.89% |
Relationship between retention rate and number of strategies used
Identifying strongest independent predictors of retention rate
Estimate | CI (Lower - Upper) |
P
| I2 | |
---|---|---|---|---|
Model 1: Continuous total number of retention strategy types | 99.86% | |||
Barriers | 0.17 | 0.03–0.32 | 0.02* | |
Community | −0.03 | − 0.18 - 0.11 | 0.63 | |
Follow-up/reminder | −0.15 | −0.29 - -0.01 | 0.04* | |
Tracing | 0.11 | −0.06 - 0.27 | 0.22 | |
Study duration | −0.04 | −0.08 - 0.00 | 0.06 | |
Number of waves | 0.00 | −0.02 - 0.03 | 0.81 | |
Model 2: Binary usage of retention strategy types | 99.84% | |||
Barriers | 0.35 | −0.15 - 0.86 | 0.16 | |
Community | 0.35 | −0.14 - 0.83 | 0.16 | |
Follow-up/reminder | −0.83 | −1.40 - -0.27 | 0.00** | |
Tracing | 0.11 | −0.36 - 0.59 | 0.64 | |
Study duration | −0.03 | −0.08 - 0.01 | 0.10 | |
Number of waves | 0.01 | −0.02 - 0.03 | 0.61 | |
Model 3: All individual strategies with p < 0.1 | 99.85% | |||
Tracing - Locator form documentation | 0.59 | −0.44 - 1.62 | 0.26 | |
Follow-up - Reminder Phone call | −0.72 | −1.20 - -0.25 | 0.00** | |
Community - Thank you and birthday cards | 0.44 | −0.11 - 0.98 | 0.12 | |
Barriers - Site and home visits | 0.42 | −0.05 - 0.88 | 0.08 | |
Barriers - Consistency in research staff | 0.39 | −0.42 - 1.20 | 0.34 | |
Barriers - Alternative method of data collection | 0.59 | 0.14–1.05 | 0.01** | |
Study duration | −0.04 | − 0.08 - − 0.00 | 0.05* | |
Number of waves | -0.00 | −0.03 - 0.02 | 0.89 |