Norms and Attitudes about Being an Active Bystander: Support for Telling Adults about Seeing Knives or Guns at School among Greater London Youth.

A detailed understanding of the factors associated with support among youth for reporting a knife or gun at school to an adult is essential to inform violence prevention initiatives. However, no studies have empirically assessed attitudes about support for reporting among secondary school students in Greater London nor perceived norms about such support among peers. Thus, this study explores whether students misperceive peer norms about support for telling adults about seeing weapons at school. Anonymous surveys were completed by 7401 youth (52% female; 43% White; mean age 11.8 years) in school years 4-11 in 45 school cohorts in a greater London borough between 2007 and 2012. Students reported both personal support about reporting weapons to several categories of adults and whether they perceived most other students at their school to support reporting weapons to adults in each category. Most students (64-78% on average) in most cohorts personally thought that students should report seeing a weapon at school to head teachers, police/security guard, teachers/counselors, and parent/other adult relatives. However, 34-44% of students erroneously thought that the majority of their peers did not support reporting to these adults. Perceived norms predicted personal support for reporting, adjusting for the prevalence of actual support at one's school and other factors. Pervasive norm misperceptions about reporting may contribute to a less safe environment.

Actual Versus Perceived HIV Testing Norms, and Personal HIV Testing Uptake: A Cross-Sectional, Population-Based Study in Rural Uganda.

HIV testing is an essential part of treatment and prevention. Using population-based data from 1664 adults across eight villages in rural Uganda, we assessed individuals' perception of the norm for HIV testing uptake in their village and compared it to the actual uptake norm. In addition, we examined how perception of the norm was associated with personal testing while adjusting for other factors. Although the majority of people had been tested for HIV across all villages, slightly more than half of men and women erroneously thought that the majority in their village had never been tested. They underestimated the prevalence of HIV testing uptake by 42 percentage points (s.d. = 17 percentage points), on average. Among men, perceiving that HIV testing was not normative was associated with never testing for HIV (AOR = 2.6; 95% CI 1.7-4.0, p < 0.001). Results suggest an opportunity for interventions to emphasize the commonness of HIV testing uptake.

Misperceived norms and personal sugar-sweetened beverage consumption and fruit and vegetable intake among students in the United States.

Perceptions of peer food and beverage consumption norms may predict personal consumption. Yet actual peer norms may be misperceived. Data were collected from adolescents in grades 6-12 (n = 5841) in 13 schools across six regionally diverse states via an anonymous online survey. The male and female averages for the number of sugar-sweetened beverages (SSBs) personally consumed per day were significantly lower than average perceptions of the typical number of SSBs consumed by peers. Inversely, the male and female averages for the number of fruit and vegetable (FV) servings personally consumed per day were significantly higher than average perceptions of typical FVs consumed by peers. Among the majority of male and female grade cohorts, the median SSB consumption was 1 drink per day and the median FV intake was 3 servings per day. Regression analyses found a strong relationship between personal consumption and perceived peer norms about male and female consumption (ß â€¯= 0.56, p < .001 for perceived male norm among male students and ß â€¯= 0.52, p < .001 for perceived female norm among female students about SSB consumption, for example), adjusting for sociodemographic characteristics and actual consumption norms. Overall, 65% and 67% of students overestimated average SSB consumption among males and females in their grade cohort, respectively, while less than 5% underestimated these norms. In addition, 49% and 52% of students underestimated average FV intake among males and females in their grade cohort, respectively, while only about 25-30% overestimated the norm. There was little difference in male and female students' estimations of peer norms. Unhealthy misperceptions of SSB norms and FV norms existed across all student categories and grade cohorts, which may contribute to unhealthy personal dietary patterns.

Misperception of peer weight norms and its association with overweight and underweight status among adolescents.

Previous research has revealed pervasive misperceptions of peer norms for a variety of behaviors among adolescents such as alcohol use, smoking, and bullying and that these misperceptions are predictors of personal behavior. Similarly, misperception of peer weight norms may be a pervasive and important risk factor for adolescent weight status. Thus, the comparative association of actual and perceived peer weight norms is examined in relation to personal weight status. Secondary school students in 40 middle and high schools (n = 40,328) were surveyed about their perceptions of the peer weight norm for same gender and grade within their school. Perceived norms were compared to aggregate self-reports of weight for these same groups. Overestimation of peer weight norms by more than 5 % occurred among 26 % of males and 20 % of females (by 22 and 16 lb on average, respectively). Underestimation occurred among 38 % of males as well as females (by 16 and 13 lb on average, respectively). Personal overweight status based on body mass index (BMI) was much more prevalent among respondents who overestimated peer weight norms as was personal underweight status among respondents who underestimated norms. Perception of the peer norm was the strongest predictor of personal BMI among all personal and school variables examined for both male and female students. Thus, reducing misperceived weight norms should be given more attention as a potential avenue for preventing obesity and eating disorders.

Evaluation of a universal point-of-issue assay for bacterial detection in buffy coat platelet components.

Bacterial contamination of platelet concentrates poses a major post-transfusion infectious risk. This study was aimed at evaluating the efficacy of the BacTx(®) assay (Immunetics Inc.) for bacterial detection in leucocyte-reduced buffy coat platelet pools and for its sensitivity in detecting clinical isolates, including bacteria that form surface-attached aggregates (biofilm positives). Platelet pools were inoculated at bacterial concentrations of 0·8-13 CFU/ml. The BacTx(®) assay detected all species at concentrations ≥10(3)  CFU/ml within 20-69 h of platelet incubation. Detection of slow-growing and biofilm-forming strains was delayed in comparison with the other strains. This assay could be used as a point-of-issue method to increase the safety of the platelet supply.

Bacterial growth in red blood cell units exposed to uncontrolled temperatures: challenging the 30-minute rule.

BACKGROUND AND OBJECTIVES: The '30-min rule' requires discarding red blood cells (RBCs) exposed to uncontrolled temperatures for >30 min to ensure safe RBC transfusion. This study was aimed at determining whether multiple room temperature (RT) exposures promote bacterial growth. MATERIALS AND METHODS: Pooled and split RBC units were inoculated with ~1 CFU/ml of Serratia marcescens, Yersinia enterocolitica, Escherichia coli or Staphylococcus epidermidis. Control units remained in storage, while test units were exposed to RT for six 30-min or three 60-min intervals. Bacterial concentrations and endotoxin levels were determined after each exposure and at 42 days of storage. RBC core temperature and RT were monitored in mock units with Escort iLog temperature loggers. A mixed model was used for statistical analyses. RESULTS: Red blood cell core temperature reached 10.7 ± 0.4°C and 14.2 ± 0.2°C during 30- and 60-min exposures, respectively. Staphylococcus epidermidis and E. coli did not grow in either control or exposed RBCs. Yersinia enterocolitica concentration and endotoxin levels were similar in both control and test units. Serratia marcescens concentration and endotoxin levels were higher in exposed units; however, differences between units exposed for 30 min or 60 min were not observed. CONCLUSION: There is no added risk to RBC safety by increasing RT exposures to 60 min with each removal from storage for up to a total of 3 h during RBC shelf life. Therefore, extending the 30-min limitation in RBCs exposed to uncontrolled temperatures to 60 min should be considered by regulatory agencies.

Overestimation of alcohol consumption norms as a driver of alcohol consumption: a whole-population network study of men across eight villages in rural, southwestern Uganda.

BACKGROUND AND AIMS: Little is known about how perceived norms about alcohol consumption may influence high alcohol consumption rates in Uganda. This study estimated the accuracy of perceived norms about men's alcohol consumption and estimated the association between perceived norms and personal alcohol consumption. DESIGN: Cross-sectional, whole-population, sociocentric social network study. SETTING: Eight rural villages in Rwampara District, southwestern Uganda in 2016-18. PARTICIPANTS: A total of 719 men aged 18 years and older (representing 91% of permanent resident men). MEASUREMENTS: Self-reported frequent (≥ 4 days per week) and heavy alcohol consumption (six or more drinks on one occasion, more than three occasions of intoxication, or spending an excessive amount on alcohol). Participants also reported whether they thought most other men in their village engaged in frequent and heavy alcohol consumption (perceived norms). Using the network study design, we calculated alcohol consumption behavior within villages and social networks. Perceived norms were compared with aggregated self-reports. Multivariable Poisson regression models were used to estimate the association between perceived norms and individual behavior. FINDINGS: Throughout villages, frequent and heavy alcohol consumption ranged from 7 to 37%. However, 527 (74%) participants perceived, contrary to fact, that most other men in their villages frequently consumed alcohol, and 576 (81%) perceived that most others heavily consumed alcohol. Overestimation of alcohol consumption by others was pervasive among socio-demographic subgroups and was present irrespective of the actual consumption behavior at the village level and within social networks. Men who misperceived these alcohol consumption behaviors as being common were more likely to engage in frequent [adjusted relative risk (aRR) = 3.98; 95% confidence interval (CI) = 1.69-9.34) and heavy (aRR = 4.75; 95% CI = 2.33-9.69) alcohol consumption themselves. CONCLUSIONS: Most men in eight rural Ugandan villages incorrectly thought that frequent and heavy alcohol consumption were common among men in their villages. These misperceived norms had a strong positive association with individual drinking behavior.

Adolescent Tobacco Use and Misperceptions of Social Norms Across Schools in the United States.

OBJECTIVE: This study assesses tobacco use norm misperceptions by distinguishing between perceived and actual peer norms for both tobacco use attitudes and behavior, and examines the association between perceived norms and personal use among U.S. students in Grades 6-12. METHOD: Anonymous self-report surveys were conducted with 28,070 students across 64 schools in 11 U.S. states between 1999 and 2017. RESULTS: Although 77% of students said tobacco use is never good, 64% of students thought that most students in their grade believed that use is acceptable. Similarly, although 79% of students reported never using tobacco, 85% of students perceived that most students in their grade typically use tobacco, with 66% thinking that peers use monthly or more often. Substantial norm misperception existed regardless of student and school factors, increasing by grade. Perceiving that most peers thought tobacco use is acceptable was highly predictive of personal attitude, and perceiving tobacco use as the norm among same-grade peers strongly predicted personal tobacco use, even after we adjusted for actual peer use prevalence and other factors. Males' perception of the male peer norm was a stronger predictor of personal use than was their perception of the female peer norm. Females' perceptions of sex-specific norms were associated with personal use, each at about the same magnitude. CONCLUSIONS: Norm misperceptions are pervasive across a diversity of students and schools, whereas perceptions of peer norms about tobacco use are highly associated with personal attitude and use. Results suggest that population-wide interventions correcting these misperceptions may help reduce tobacco use broadly among youth.

Self-efficacy and participation in physical and social activity among older adults in Spain and the United States.

PURPOSE: We explored Bandura's self-efficacy theory as applied to older adult (aged 63-92) participation in physical and social activity in a cross-cultural study. DESIGN AND METHODS: Older adults in Spain (n = 53) and the United States (n = 55) completed questions regarding self-efficacy, outcome expectancy, and participation in physical and social activities. RESULTS: Self-efficacy significantly predicted both physical and social activity in both Spain and the United States. Outcome expectancy did not significantly predict either activity, nor did education, gender, or overall health. Modified and new self-efficacy measures proved reliable in both samples. IMPLICATIONS: This study enhances understanding of how self-efficacy motivates participation in physical activity, as noted in previous studies, as well as provides a new understanding of what motivates participation in social activities. The high reliability of the new measures used in this study provides evidence for further use of these measures in other contexts. It is important to note that this study further supports the use of Bandura's theory of self-efficacy for cross-cultural applications.

Declining negative consequences related to alcohol misuse among students exposed to a social norms marketing intervention on a college campus.

OBJECTIVE: The authors examined whether alcohol-related negative consequences decreased among students exposed to an intervention. PARTICIPANTS: Beginning in 1999, approximately 2,500 randomly selected undergraduates from a 4-year US university annually participated in a Web-based survey over 6 years. METHODS: The educational intervention used social norms initiatives. Main outcome measures included recall of intervention, estimated blood alcohol content (eBAC) when drinking, and 10 negative consequences from alcohol within the past year. RESULTS: First-year students recalling exposure had lower odds of negative consequences (odds ratio [OR] = 0.78, 95% confidence interval [CI] = 0.64-0.95) and of having an eBAC higher than .08 (OR = 0.76, 95% CI = 0.62-0.92). Over the 6 study years, the odds among all participants of experiencing (a) none of 10 alcohol consequences nearly doubled (OR = 2.13, 95% CI = 1.82-2.49) and (b) multiple consequences decreased by more than half (OR = 0.43, 95% CI = 0.36-0.50). CONCLUSIONS: These findings have important implications for US colleges and universities engaged in the reduction of harm associated with alcohol misuse.

Accuracy of Estimated Blood Alcohol Concentration Norms From College Student Drinking Survey Data: Verification Using Matched Late-Night Breath Measurements.

OBJECTIVE: This study assesses the accuracy of estimated blood alcohol concentration (eBAC) from survey data in a college student sample using six computational methods from the literature. Corrections for heavy-drinker metabolic rate and preabsorptive error are added to the estimating formula. METHOD: Late-night interception of 2,282 students returning to residence halls every night of the week was used in a double-blind breath test and survey about typical and current-evening alcohol use and body characteristics. RESULTS: Measured breath alcohol concentration (BrAC) was used to assess the accuracy of the computational models. The Seidl method yielded the best performance, with further reduction in error observed when a heavy-drinker metabolic rate correction was applied. In situations when an intercept occurred shortly after alcohol consumption, a correction for alcohol absorption kinetics further reduced error. Despite significant remaining error of estimates for a substantial minority of individuals, using the refined calculation of an eBAC permitted computation of low risk/low impairment (<.05 g/dl) and high risk/high impairment (≥.08 g/dl) prevalences that were virtually identical to the corresponding prevalences revealed using the data from the BrAC measurements. CONCLUSIONS: In late-night intercepts of college students, an eBAC can be calculated from survey data with only modest accuracy for individuals. This measure can quite accurately measure norms, however, with regard to actual BAC levels in circumstances in which students are returning from activities that might include heavy or high-risk drinking.

Comparison of the HL-A phenotypes of lymphocytes and kidney cells determined by the fluorochromasia cytotoxicity assay.

Correlation of leukocyte typing with homograft survival suggests that HL-A typing of white blood cells reflects the histocompatibility factors of the kidney, yet some apparently well-matched kidneys are rejected. The latter results may, in part, reflect inadequacies of typing techniques, incomplete expression of HL-A factors on white blood cells as compared with the cells of the rejected organ, or isoantigens not shared with leukocytes. In this study the kidney cells and lymphocytes (from blood or nodes) of 14 individuals were typed for HL-A factors 1, 2, 3, 5, 7, 8, 9, and 12, and factors 4a and 4b by fluorochromasia cytotoxicity. Biopsied kidney cells were prepared with 0.25% trypsin and typed fresh, after varying periods in monolayer culture or after storage in liquid nitrogen, in all cases resulting in cells which were pleomorphic but uniform in reactivity. Reproducibility of lymphocyte typing was 99%, and of kidney cell typing, 93%. The 4a factor was detected on the lymphocytes but not the kidney cells of four individuals. HL-A7 and HL-A8, in contrast, were detected on kidney cells and not lymphocytes of four and three individuals, respectively. Results were consistent within the groups of individual sera used to detect each factor. The HL-A factors detected on both kidney cells and lymphocytes never resulted in more than two alleles at each genetic sublocus. Several examples of post-rejection sera have reacted with donor kidney cells but not with lymphocytes. Kidney cells may thus be useful in compatibility tests to aid in selection of donors for a retransplant. The ability to store donor kidneys by perfusion provides time to employ kidney cells for typing and in compatibility tests, and the use of a standard cytotoxic assay makes their routine use practical. Typing kidney cells as well as lymphocytes thus offers an approach to more complete and accurate HL-A phenotyping.

Misperceptions of peer drinking norms in Canada: another look at the "reign of error" and its consequences among college students.

OBJECTIVE: Much research has documented extensive misperceptions of drinking norms and their negative effects in U.S. student populations. This study provides extensive research evidence documenting this phenomenon in Canadian higher education. METHODS: Data were collected in a 2003-2004 survey of students (N=5280) attending 11 institutions across Canada. Surveys were administered either to a random sample of students through the mail or to students attending a diverse selection of classes. RESULTS: Regardless of the actual drinking norm on each campus, students most commonly overestimated the alcohol consumption norms (both quantity and frequency levels) in every instance. Students' perception of their campus drinking norm was the strongest predictor of the amount of alcohol personally consumed in comparison with the influence of all demographic variables. Perception of the norm was also a much stronger predictor of personal use than the actual campus norm for consumption on each campus or the actual norm for compliance with campus regulations. Among students who personally abstain or consume lightly, misperceptions of the student drinking norms contribute to alienation from campus life. CONCLUSION: The data presented here on Canadian students extends the evidence that peer drinking norms are grossly misperceived and that these misperceptions produce a highly detrimental "reign of error" in the lives of college students. The data suggest that a broad range of students--abstainers and light drinkers as well as moderate and heavy drinkers--may benefit from implementing intervention strategies that can correct or reduce these misperceptions.

A successful social norms campaign to reduce alcohol misuse among college student-athletes.

OBJECTIVE: This study examines the impact of a social norms intervention to reduce alcohol misuse among student-athletes. The intervention was designed to reduce harmful misperceptions of peer norms and, in turn, reduce personal risk. METHOD: A comprehensive set of interventions communicating accurate local norms regarding alcohol use targeted student-athletes at an undergraduate college. An anonymous survey of all student-athletes was conducted annually for 3 years (2001: n = 414, 86% response; 2002: n = 373, 85% response; and 2003: n = 353, 79% response). A pre/post comparison of student-athletes was conducted separately for new and ongoing athletes at each time point to isolate any general time period effects from intervention effects. A cross-sectional analysis of student-athletes with varying degrees of program exposure was also performed. RESULTS: The intervention substantially reduced misperceptions of frequent alcohol consumption and high-quantity social drinking as the norm among student-athlete peers. During this same time period, frequent personal consumption, high-quantity consumption, high estimated peak blood alcohol concentrations during social drinking, and negative consequences all declined by 30% or more among ongoing student-athletes after program exposure. In contrast, no significant differences across time were seen for new student-athletes each year with low program exposure. Among student-athletes with the highest level of program exposure, indications of personal misuse were at least 50% less likely on each measure when compared with student-athletes with the lowest level of program exposure. CONCLUSIONS: This social norms intervention was highly effective in reducing alcohol misuse in this high-risk collegiate subpopulation by intensively delivering data-based messages about actual peer norms through multiple communication venues.

Misperceiving the college drinking norm and related problems: a nationwide study of exposure to prevention information, perceived norms and student alcohol misuse.

OBJECTIVE: This study examined (1) the prevalence of misperceptions of college student drinking norms across campuses nationwide, (2) the importance of perceived norms in predicting high-risk drinking, (3) the association of exposure to alcohol education information with students' perceptions of campus drinking norms and (4) the differences in high-risk drinking rates between schools where exposure to alcohol information is associated with more accurately perceived norms and schools where exposure to information is unrelated to perceptions or is associated with greater misperceptions. METHOD: Multivariate analyses were used to analyze an aggregate database of the National College Health Assessment survey administered to 76,145 students from 130 colleges and universities nationwide from spring 2000 through spring 2003. RESULTS: Regardless of the actual campus drinking norm, a consistently large percentage of students nationwide overestimated the quantity of alcohol consumed by their peers. Students' perception of their campus drinking norm was the strongest predictor of the amount of alcohol personally consumed in comparison with the influence of all demographic variables. Perception of the norm was also a much stronger predictor when compared with the actual campus norm. Reduced levels of high-risk drinking and negative consequences were found among students attending the relatively few schools where exposure to prevention information was associated with less exaggerated perceptions of the drinking norm compared with students attending other schools. CONCLUSIONS: Misperceived drinking norms are a pervasive problem. Schools that do not seek to reduce these misperceptions with their prevention information are neglecting a potentially powerful component of prevention.

Dying right in theory and practice. What do we really know of terminal care?

Despite the widely held belief that hospices treat dying patients differently than conventional hospitals do, few systematic comparisons exist. We reviewed medical charts to study the terminal care practice at one hospital and two inpatient hospices. As expected, hospital patients had more diagnostic tests and higher laboratory charges than patients in either hospice did. Yet physicians' notes about patients' families or nonmedical aspects of illness were infrequent at all three institutions. Furthermore, analgesic use and the frequency of nurses' notes about nonmedical or family issues differed between hospices: sometimes one hospice, sometimes the other, resembled the hospital closely. Hence, some common assumptions about hospice care appear inaccurate. We believe that health professionals who attend dying patients--whether in hospitals or hospices--have an obligation to examine their terminal care practices critically and to develop standards appropriate for their institutions.

Patterns of T lymphocyte changes with human immunodeficiency virus infection: from seroconversion to the development of AIDS.

CD4 and CD8 T lymphocytes of three groups of men infected by the human immunodeficiency virus (HIV) were examined twice yearly for 36 months to elucidate the temporal trends in T lymphocytes during infection. The three groups were 37 HIV seroconverters, 304 prevalent HIV seropositives remaining free of the acquired immunodeficiency syndrome (AIDS), and 69 men who developed AIDS during observation. Six months before seroconversion, CD4 levels were similar among HIV seroconverters and 356 seronegative controls. Within 18 months of seroconversion, mean CD4 levels fell to the level of the prevalent seropositives at study entry. From there, the rate of decline slowed. CD8 lymphocyte counts rose dramatically at seroconversion. Among AIDS-free prevalent seropositives, CD4 levels fell steadily over 36 months of observation. By contrast, CD8 cell levels rose slowly. Among men who developed AIDS, mean CD4 levels fell more rapidly again during the 18 months prior to diagnosis. CD8 cell levels remained elevated until 6-12 months before diagnosis, when they began to fall.

Heterosexual transmission of human immunodeficiency virus type 1 from transfusion recipients to their sex partners.

Using lookback procedures and other methods, we identified and then prospectively followed human immunodeficiency virus type 1 (HIV-1)-infected transfusion recipients and their sex partners to determine AIDS incidence and risks of heterosexual transmission of HIV-1. At enrollment, 7 of 32 (21.9%) female partners of male recipients were themselves infected with HIV-1, as compared with none of 14 male partners of female recipients (p = 0.08). No additional episodes of transmission were observed. The prevalence of advanced immunodeficiency at enrollment was similar in male and female recipients. Male recipients with advanced immunodeficiency (CD4+ lymphocyte count < or = 0.20 x 10(9)/L or a history of clinical AIDS) at enrollment were more likely to have infected their female partners (odds ratio = 7.9; p = 0.03) than men with neither condition. Similarly, AIDS-free survival, as estimated by the product-limit method, was lower among male transmitters than among male nontransmitters (p = 0.01). Transmission was not associated with frequency of unprotected vaginal intercourse. Our data suggest that HIV-1-infected men who develop immunodeficiency rapidly are more likely to infect their sex partners and that the greater efficiency of male-to-female HIV-1 transmission is not explained by a greater number of sexual contacts or more advanced immunodeficiency in index subjects.

Impact of medical ethics consultations on physicians: an exploratory study.

PURPOSE AND METHODS: Despite the increasing availability of medical ethics consultations, little research addresses the impact of these consultations on physicians. Therefore, we surveyed physician-requesters and reviewed medical charts to evaluate the 44 ethics consultations concerning individual patients at our university medical center over an 18-month period. RESULTS: The physicians who requested these consultations said 14 consultations identified previously unrecognized ethical issues, and 18 changed patient management considerably. The medical charts showed that the most frequently overlooked issue was inappropriate family decisions for incompetent adult patients (five consultations) and the most frequent management changes involved withholding cardiopulmonary resuscitation (12 consultations). CONCLUSIONS: Ethics consultations appeared to have considerable impact on physicians in conducting patient care.

Impact of legal liability, family wishes, and other "external factors" on physicians' life-support decisions.

PURPOSE: The purpose of this study was to determine the impact of external factors on physicians' life-support decisions. "External factors" are those factors that promote the interests of people other than the patient. Examples of external factors include physician legal liability and family wishes about patient care. SUBJECTS AND METHODS: A nationwide sample consisted of 300 randomly selected physician-members from the American Society of Law and Medicine (ASLM) and 300 from the Society for Critical Care Medicine (SCCM); 179 ASLM physicians (60%) and 165 SCCM physicians (55%) responded. A mailed questionnaire presented three cases, each requiring the physician to make a life-support decision. For each case, the physician chose one of several life-support options and rated the importance to his or her decision of specific "decision factors," including some external factors. We assumed the physician would choose the management option supported by the decision factors that the physician considered most important. For this reason, we used discriminant analysis to identify the factors whose importance ratings best predicted management choices. RESULTS: In the first case, 46% of ASLM respondents and 55% of SCCM respondents chose to stop the ventilator of a chronically comatose patient with unknown preferences about life support. Thirty-one percent of ASLM and 27% of SCCM respondents chose to continue the ventilator, and 21% of ASLM and 14% of SCCM respondents chose to apply for a judicial decision. Importance ratings for the external factor, physician legal liability, best predicted management choices. In the second case, 95% of ASLM and 94% of SCCM respondents chose to resuscitate a cancer patient at the patient's request; 3% of ASLM and 4% of SCCM respondents chose no resuscitation. Importance ratings for patient preferences best predicted management choices. In the third case, 38% of ASLM and 35% of SCCM respondents honored a stroke patient's previous refusal of tube feedings, but 59% of ASLM and 62% of SCCM respondents authorized tube feedings in order to secure nursing home placement. Importance ratings for patient preferences best predicted management choices in this case. External factors impacted management choices considerably in the first case and more modestly in the second and third cases. CONCLUSION: External factors impact the life-support decisions of physicians. Physician legal liability may have an especially great impact on these decisions when patients' preferences are not known.