EDITORIALS
easily obtained during the ED visit. The National Agenda calls for a minimal data set to be created so that data linkage can be promoted. Emergency physicians can play an active role in community education about injury prevention, the cost of injury to society, how to a c c e s s the medical system, and how to respond to an emergency. First responders and EMS personnel need training in injury control, a c u t e care, mechanisms and patterns of injury, and the value of accurate data. Other physicians need learned advice and counsel about the issues of trauma care and what role they may play in the developing agenda. Discussions and presentations of trauma systems, the cost of injury, and the fundamentals of injury control must be integrated into medical schools, residency programs, and annual meetings. Emergency physicians must use their administrative skills and medical knowledge to strengthen EMS systems, coordinate use of regional resources, and build medical and community coalitions. Emergency medicine as a specialty must continue its leadership role in the development of trauma systems, but more importantly, it must engender and support a legion of knowledgeable delegates who can shoulder the responsiblity of today and envision the world of tomorrow.
Ricardo Martinez, MD, FACEP Stanford University Hospital Pale Alto, California 1. Committee on Trauma and Committee on Shock: Accidental death and disability: The neglected disease of modern socity. Washington, DC National Research Council/National Academy of Sciences, 1966, 2. National Research Council, Committee on Trauma Research. Injury in America: A continuing public heatth problem. Washington, DC National Academy Press, 1985. 3. National Research Council, Committee on Trauma Research. Injury control: A reveiw of the status and progress of the Injury Control Program at the Centers for Disease Control. Washington, DC National Academy Press, 1988. 4. Rice D, MacKenzie EJ, etal: Cost of injury in the United States: A report to Congress. San Francisco, Institute for Health and Aging, University of California; and Baltimore, Injury Prevention Center, Johns Hopkins University, 1989. 5. Optimal hospital resources for care of the seriously injured. BuffAm Coil Surg'1978;61:15-22. 6. American College of Emergency Physicians: Guidelines for trauma care systems. Ann EmergMed 1987;16:459-464.
Use of Statistical Tests A wide assortment of statistical tests is used in medical research publications to analyze experimental data. Many of these tests are applicable in a limited set of circumstances, and the reasons for their use may therefore not be readily apparent to the reader. A recent article concluded that five tests accounted for the bulk of the statistics used in the three largest emergency medicine journals.1 However, similar information on the frequency of use of less common statistical tests is unavailable. We conducted a retrospective review of all statistical tests used in 344 manuscripts published as original contributions i n Annals of Emergency Medicine from March 1988 through March 1991. We did not evaluate whether tests were used appropriately. Each test was recorded once per article, regardless of the number of analyses performed with that test; results are shown (Table). More than two thirds of the articles examined used some type of statistical test. The remaining articles (103) used descriptive
86/171
techniques (eg, mean or median) or had no analysis. No article used more than seven different tests. Four tests with broad applicability (two parametric and two nonparametric) were used for nearly 75% of the reported statistics. Conversely, 11 different tests comprised just over 3% of the Table. Statistical tests reported in the Annals of Emergency Medicine original contributions section, from March ] 988 through March 1991 No. of Articles Using Test
%
Parametric Student's t (type not specified) Student's t{one-tailed) Student's t(two-tailed) Student's t (paired) Student's t(Bonferroni} Student's t(total)
73 2 24 17 6 12.2
31.3 0.9 I0.3 7.3 2.6 52.4
ANOVA/Ftest Regression analysis Pearson correlation Tukey Z Newman-Keuls Duncan Dunnett Scheffe Dunn Discriminant analysis Total
48 22 12 8 8 4 3 2 2 1 1 233
20.6 9.4 5.2 3.4 3.4 1.7 1.3 0.9 0.9 0.4 0.4 100
Nonparametric Z2 X 2 Yates Z2 (total}
106 13 119
45.3 5.8 50.9
Fisher's exact (type not specified) Fisher's exact (one-tailed) Fisher's exact (two tailed) Fisher's exact (total)
46 2 4 52
19.7 0.9 1.7 22,2
Mann-Whitney U Wilcoxon sign rank Kruskal-Wallis Wilcaxan rank sum McNemar Kolmogerov Smirnov ManteFHaenszel Friedman Spearman rank Cochran Q Sign Wiicoxon-Mann-Whitney Leg rank Kendall-tau Proe Nparlway (sic} Total
14 11 9 8 5 3 3 2 2 1 1 1 1 1 1 234
&O 4.7* 3.8 3.4 2.I 1.3 1.3 0.9 0.9 0.4 0.4 0.4 0.4 0.4 0.4 100
Name of Test
No specific test mentioned Articles using descriptive methods
4 103
N = 344 articles examined. *Rounded to the nearest tenth of percent.
ANNALSOF EMERGENCY MEDICINE
21:2
FEBRUARY1992
EDITORIALS
reported statistics. Four articles mentioned statistical significance values but never indicated which test was used. In one article, a computer program procedure was mistakenly reported as an actual statistical test. This descriptive analysis suggests two eonelusions. First, as suggested by Menegazzi et al, residency programs should refine their statistical teaching curriculum. 1 Because most emergency medicine research artieles appear to use only a handful of statistical tests, emphasizing an understanding of the few common tests while acknowledging the value of uncommon tests will match the burden of information to the utility of the knowledge and may increase retention. In turn, this may decrease frustration in what is an often challenging portion of the residency curriculum. Second, although each of the tests tabulated has specific charaeteristics that make it useful in various cireumstances, authors seldom justified their choice of an uncommon test. It has been suggested that little-known tests with restrictive criteria for use might be used by authors unable to obtain desired results with the more common and broadly applicable tests. 2 Also, many tests have subtle variations that can affect statistical interpretation. As examples, the Student's t test and Fisher's exact tests may be one-tailed or two-tailed. In the majority of instances that these tests were used, the authors did not speeify which analysis was applied. These problems are not unique to the emergency medicine literature. 3 The eurrent "Information for Authors" in Annals requires that statistical tests be identified and referenced. An informal review of other biomedical journals reveals similar brief guidelines. We suggest that in addition to identifying the test used, authors specify the reasons that each statistical test was chosen, particularly if the test is uncommon. By revealing the motive for choosing a given test, authors will clarify their data interpretation and more fully describe the rationale of their conclusions. RobertDe Lorenzo,MD James Olson, PhD Departmentof EmergencyMedcine Wright State University Dayton, Ohio 1. Menegazzi JJ, Yealy DM, Harris JH: Methods of data analysis in the emergency medicine literature. Am J EmergMed 1991 ;9:225-227. 2. Elenbaas RM, Elenbaas JK, Cuddy PG: Evaluating the medical literature: Part II. Statistical analysis. Ann EmergMed 1983;12:616-620. 3. McKinney WP, Young M J, Hartz A, et al: The inexact use of Fisher's exact test in six major medical journals. JAMA 1989;261:3430-3433.
An Academic Status Report for Emergency Medicine See related article, p 193. This issue of Annals contains an address presented by Dr Robert Petersdorf at the 1991 Annual Meeting of the Society for Academic Emergency Medicine. Dr Petersdoff, one of the best known physicians in the world, has served as a medical school faculty member
FEBRUARY 1992
21:2
ANNALS OF EMERGENCY MEDICINE
for Johns Hopkins University, the University of Washington, Harvard University, the University of California at San Diego, and (currently) Georgetown University. He has served as President of the Assoeiation of American Medical Colleges since 1986. His contributions to academic medicine have been legion. In 199I, as we the clinicians, educators, and researchers in academic emergency medicine move toward integration into organized academia, the guidance of the president of the American Association of Medical Colleges is extremely pertinent. The science, practice, and administration of emergency care are being pursued in complex times. Academic emergeney physicians must provide care for an increasing number of indigent patients with complicated health care needs that commonly are not being met elsewhere, either in the private setting or in the confines of the teaching hospital. There is an increased emphasis on ambulatory practice and diagnostics in the emergency department that further expands the educational and clinical role of the emergency physician in the aeademie setting. As an academic specialty, emergency medicine has achieved much in its short history. The perspective of Dr Petersdorf is useful both as a measure of achievement and as a guide for future growth. As educators of future emergency physicians, we must be eognizant of the demand for, geographic practice location of, and minority representation of our graduates. Dr Petersdoff notes that the demand for emergency physicians needs better definition and attention. Certainly the immediate need for educators is signifieant, and there is a shortage of physicians who practice rural emergency medicine. Nonetheless, to avoid the dilemma of other specialties, we will need to carefully define future manpower needs and the optimal means to meet those needs. Of special note is the fact that minorities in medicine are underrepresented as a whole. Emergency medicine should initiate programs targeted at premedical undergraduates that will increase minority representation. The recruitment of undergraduate minority students in emergency medical services positions and research laboratories "affiliated with emergency medicine residency programs should help this process. Emergency medicine programs may call on the local business community to aid this enteilarise through Dmergency medical services and emergency medicine research training scholarships. Dr Petersdorf advises emergency medicine not to pursue "primary care" designation. The value of such designation will of course be dependent on any resultant financial support provided by Congress for specialty education in areas designated as primary care. In an environment where the majority of medical care for a significant portion of the US population by default is provided through EDs, there may be both justification and an incentive for primary care designation. Dr Petersdorf notes that emergency care is expensive. In light of increasing governmental control of the health care industry, continued careful appraisal of the cost of delivering emergency 11~
172/ 87
easily obtained during the ED visit. The National Agenda calls for a minimal data set to be created so that data linkage can be promoted. Emergency physicians can play an active role in community education about injury prevention, the cost of injury to society, how to a c c e s s the medical system, and how to respond to an emergency. First responders and EMS personnel need training in injury control, a c u t e care, mechanisms and patterns of injury, and the value of accurate data. Other physicians need learned advice and counsel about the issues of trauma care and what role they may play in the developing agenda. Discussions and presentations of trauma systems, the cost of injury, and the fundamentals of injury control must be integrated into medical schools, residency programs, and annual meetings. Emergency physicians must use their administrative skills and medical knowledge to strengthen EMS systems, coordinate use of regional resources, and build medical and community coalitions. Emergency medicine as a specialty must continue its leadership role in the development of trauma systems, but more importantly, it must engender and support a legion of knowledgeable delegates who can shoulder the responsiblity of today and envision the world of tomorrow.
Ricardo Martinez, MD, FACEP Stanford University Hospital Pale Alto, California 1. Committee on Trauma and Committee on Shock: Accidental death and disability: The neglected disease of modern socity. Washington, DC National Research Council/National Academy of Sciences, 1966, 2. National Research Council, Committee on Trauma Research. Injury in America: A continuing public heatth problem. Washington, DC National Academy Press, 1985. 3. National Research Council, Committee on Trauma Research. Injury control: A reveiw of the status and progress of the Injury Control Program at the Centers for Disease Control. Washington, DC National Academy Press, 1988. 4. Rice D, MacKenzie EJ, etal: Cost of injury in the United States: A report to Congress. San Francisco, Institute for Health and Aging, University of California; and Baltimore, Injury Prevention Center, Johns Hopkins University, 1989. 5. Optimal hospital resources for care of the seriously injured. BuffAm Coil Surg'1978;61:15-22. 6. American College of Emergency Physicians: Guidelines for trauma care systems. Ann EmergMed 1987;16:459-464.
Use of Statistical Tests A wide assortment of statistical tests is used in medical research publications to analyze experimental data. Many of these tests are applicable in a limited set of circumstances, and the reasons for their use may therefore not be readily apparent to the reader. A recent article concluded that five tests accounted for the bulk of the statistics used in the three largest emergency medicine journals.1 However, similar information on the frequency of use of less common statistical tests is unavailable. We conducted a retrospective review of all statistical tests used in 344 manuscripts published as original contributions i n Annals of Emergency Medicine from March 1988 through March 1991. We did not evaluate whether tests were used appropriately. Each test was recorded once per article, regardless of the number of analyses performed with that test; results are shown (Table). More than two thirds of the articles examined used some type of statistical test. The remaining articles (103) used descriptive
86/171
techniques (eg, mean or median) or had no analysis. No article used more than seven different tests. Four tests with broad applicability (two parametric and two nonparametric) were used for nearly 75% of the reported statistics. Conversely, 11 different tests comprised just over 3% of the Table. Statistical tests reported in the Annals of Emergency Medicine original contributions section, from March ] 988 through March 1991 No. of Articles Using Test
%
Parametric Student's t (type not specified) Student's t{one-tailed) Student's t(two-tailed) Student's t (paired) Student's t(Bonferroni} Student's t(total)
73 2 24 17 6 12.2
31.3 0.9 I0.3 7.3 2.6 52.4
ANOVA/Ftest Regression analysis Pearson correlation Tukey Z Newman-Keuls Duncan Dunnett Scheffe Dunn Discriminant analysis Total
48 22 12 8 8 4 3 2 2 1 1 233
20.6 9.4 5.2 3.4 3.4 1.7 1.3 0.9 0.9 0.4 0.4 100
Nonparametric Z2 X 2 Yates Z2 (total}
106 13 119
45.3 5.8 50.9
Fisher's exact (type not specified) Fisher's exact (one-tailed) Fisher's exact (two tailed) Fisher's exact (total)
46 2 4 52
19.7 0.9 1.7 22,2
Mann-Whitney U Wilcoxon sign rank Kruskal-Wallis Wilcaxan rank sum McNemar Kolmogerov Smirnov ManteFHaenszel Friedman Spearman rank Cochran Q Sign Wiicoxon-Mann-Whitney Leg rank Kendall-tau Proe Nparlway (sic} Total
14 11 9 8 5 3 3 2 2 1 1 1 1 1 1 234
&O 4.7* 3.8 3.4 2.I 1.3 1.3 0.9 0.9 0.4 0.4 0.4 0.4 0.4 0.4 100
Name of Test
No specific test mentioned Articles using descriptive methods
4 103
N = 344 articles examined. *Rounded to the nearest tenth of percent.
ANNALSOF EMERGENCY MEDICINE
21:2
FEBRUARY1992
EDITORIALS
reported statistics. Four articles mentioned statistical significance values but never indicated which test was used. In one article, a computer program procedure was mistakenly reported as an actual statistical test. This descriptive analysis suggests two eonelusions. First, as suggested by Menegazzi et al, residency programs should refine their statistical teaching curriculum. 1 Because most emergency medicine research artieles appear to use only a handful of statistical tests, emphasizing an understanding of the few common tests while acknowledging the value of uncommon tests will match the burden of information to the utility of the knowledge and may increase retention. In turn, this may decrease frustration in what is an often challenging portion of the residency curriculum. Second, although each of the tests tabulated has specific charaeteristics that make it useful in various cireumstances, authors seldom justified their choice of an uncommon test. It has been suggested that little-known tests with restrictive criteria for use might be used by authors unable to obtain desired results with the more common and broadly applicable tests. 2 Also, many tests have subtle variations that can affect statistical interpretation. As examples, the Student's t test and Fisher's exact tests may be one-tailed or two-tailed. In the majority of instances that these tests were used, the authors did not speeify which analysis was applied. These problems are not unique to the emergency medicine literature. 3 The eurrent "Information for Authors" in Annals requires that statistical tests be identified and referenced. An informal review of other biomedical journals reveals similar brief guidelines. We suggest that in addition to identifying the test used, authors specify the reasons that each statistical test was chosen, particularly if the test is uncommon. By revealing the motive for choosing a given test, authors will clarify their data interpretation and more fully describe the rationale of their conclusions. RobertDe Lorenzo,MD James Olson, PhD Departmentof EmergencyMedcine Wright State University Dayton, Ohio 1. Menegazzi JJ, Yealy DM, Harris JH: Methods of data analysis in the emergency medicine literature. Am J EmergMed 1991 ;9:225-227. 2. Elenbaas RM, Elenbaas JK, Cuddy PG: Evaluating the medical literature: Part II. Statistical analysis. Ann EmergMed 1983;12:616-620. 3. McKinney WP, Young M J, Hartz A, et al: The inexact use of Fisher's exact test in six major medical journals. JAMA 1989;261:3430-3433.
An Academic Status Report for Emergency Medicine See related article, p 193. This issue of Annals contains an address presented by Dr Robert Petersdorf at the 1991 Annual Meeting of the Society for Academic Emergency Medicine. Dr Petersdoff, one of the best known physicians in the world, has served as a medical school faculty member
FEBRUARY 1992
21:2
ANNALS OF EMERGENCY MEDICINE
for Johns Hopkins University, the University of Washington, Harvard University, the University of California at San Diego, and (currently) Georgetown University. He has served as President of the Assoeiation of American Medical Colleges since 1986. His contributions to academic medicine have been legion. In 199I, as we the clinicians, educators, and researchers in academic emergency medicine move toward integration into organized academia, the guidance of the president of the American Association of Medical Colleges is extremely pertinent. The science, practice, and administration of emergency care are being pursued in complex times. Academic emergeney physicians must provide care for an increasing number of indigent patients with complicated health care needs that commonly are not being met elsewhere, either in the private setting or in the confines of the teaching hospital. There is an increased emphasis on ambulatory practice and diagnostics in the emergency department that further expands the educational and clinical role of the emergency physician in the aeademie setting. As an academic specialty, emergency medicine has achieved much in its short history. The perspective of Dr Petersdorf is useful both as a measure of achievement and as a guide for future growth. As educators of future emergency physicians, we must be eognizant of the demand for, geographic practice location of, and minority representation of our graduates. Dr Petersdoff notes that the demand for emergency physicians needs better definition and attention. Certainly the immediate need for educators is signifieant, and there is a shortage of physicians who practice rural emergency medicine. Nonetheless, to avoid the dilemma of other specialties, we will need to carefully define future manpower needs and the optimal means to meet those needs. Of special note is the fact that minorities in medicine are underrepresented as a whole. Emergency medicine should initiate programs targeted at premedical undergraduates that will increase minority representation. The recruitment of undergraduate minority students in emergency medical services positions and research laboratories "affiliated with emergency medicine residency programs should help this process. Emergency medicine programs may call on the local business community to aid this enteilarise through Dmergency medical services and emergency medicine research training scholarships. Dr Petersdorf advises emergency medicine not to pursue "primary care" designation. The value of such designation will of course be dependent on any resultant financial support provided by Congress for specialty education in areas designated as primary care. In an environment where the majority of medical care for a significant portion of the US population by default is provided through EDs, there may be both justification and an incentive for primary care designation. Dr Petersdorf notes that emergency care is expensive. In light of increasing governmental control of the health care industry, continued careful appraisal of the cost of delivering emergency 11~
172/ 87
