XIII. Health Statistics and Research Kathy C. Trawick, EdD, RHIA, FAHIMA
Health Statistics and Research 369 As noted in the main Introduction section, you will be able to access some statistical formulas on the computer to use during the exam. You may not find them in any set location be prepared to look around for them a little. Of course, there are some formulas (for example: mean, median, and average) you will be responsible for knowing. When preparing for the exam, practice using the calculator located in the program accessories bar on your computer and the formulas that are provided in this text. Although some questions are included from the Commonly Computed Rates and Percentages for Hospital Inpatients, you will often be asked to interpret everyday data and/or solve questions that have more to do with common sense and good math skills than with memorized formulas. To help you distinguish among the types of questions you might expect, and to make sure you realistically evaluate your skills in this area, this chapter has been divided into four sections: 1. Statistical basics 2. Commonly computed rates 3. Data display and interpretation 4. Research and financial statistics According to the breakdown of content for both the RHIA and RHIT exams, the health statistics questions have been included in Domain II. This section not only covers statistics and research, but also may include data collection, interpretation, and presentation as well as knowledge of registries, specialized databases, and the Institutional Review Board (IRB). You should also be prepared to analyze and interpret statistical charts and graphs. Some questions will refer to a graphical representation of data when asking for the answer. Refer to the specific details of these items in the domain and subdomain competencies found in the Certification Guide. You will want to work with statistical formulas from this chapter, from your formal courses, and from previous textbooks until you get your speed up. Sometimes the length of time it takes in calculating formulas and mathematical computations can make or break you on the entire examination as far as your testing time. Thus, increasing your speed by practicing formulas can really help you at exam time. Most answers in this section should be rounded to the first decimal point. On the national examination, let the answers provided in the test be your guide, or follow the examination instructions in order to round correctly. Do not let the word problems throw you off. Some of these are quite long; look for the pertinent data. Do not panic approach word problems just as you did in your formal classes. You will have the formulas provided for you as appropriately required on the exam. For problems that you may not have a formula for, try the memory device of what did happen divided by what could have happened. Here, the what did happen is always the numerator (top number) and the what could have happened is always the denominator (bottom number). We recommend that you review the textbooks listed at the end of this chapter as you study for this section of your exam.
370 Chapter XIII Health Statistics Definitions and Formulas There are a number of important things to think about when you tackle census and occupancy statistics. First, remember that when it comes to occupancy, beds and bassinets are counted separately. This means newborn discharges are separated from the discharges of adults and children. Next, remember not to be fooled by beds set up temporarily to meet unusual admission needs; all occupancy statistics should be calculated based on approved, permanent beds only. The common rates used for census and occupancy statistics are as follows: Census Statistics Daily Inpatient Census Inpatient Service Day Total Inpatient Service Days FORMULA: Average Daily Census Total number of patients treated during a 24-hour period Services received by one inpatient in one 24-hour period Sum of all inpatient service days for each of the days in the period Total inpatient service days for a period (excluding newborns) Total number of days in the period Length of Stay Length of Stay (LOS) Total Length of Stay FORMULA: Average LOS Number of calendar days from admission to discharge Sum of the days stay of any group of inpatients discharged during a specific period Total length of stay (discharge days) Total number of discharges Bed Count Inpatient Bed Count Inpatient Bed Count Day Total Inpatient Bed Count Day Number of available hospital beds, both occupied and vacant, on any given day Counts the presence of one inpatient bed (occupied or vacant) that is set up and staffed for use in one 24-hour period Sum of inpatient bed count days for each of the days in a period Percentage of Occupancy FORMULA: Total number of inpatient service days for a period 100 Total inpatient bed count days number of days in the period
Health Statistics and Research 371 Bed Turnover Rate Direct Formula: Total number of discharges for a period Average bed count for the same period Indirect Formula: Percentage of occupancy Days in the period 100 Average length of stay NOTE: The indirect formula must be used in cases where the bed count changes during the period in question. Death (Mortality) Rates Anesthesia Death Rate Total number of deaths caused by an anesthetic agent 100 Total number of anesthetics administered Fetal Death Rate Total number of intermediate and late fetal deaths 100 (Stillbirth Rate) Total number of births (plus intermediate and late fetal deaths) Gross Hospital Total number of inpatient deaths (including newborns) 100 Death Rate Total number of discharges (including deaths and newborns) Net Hospital Number of inpatient deaths (including NB) Death Rate minus deaths <48 hours of admission 100 Total discharges (including deaths and NB, minus deaths <48 hours) Maternal Total number of maternal deaths for a period 100 Death Rate Total number of obstetrical discharges Neonatal Death Rate Total number of newborn (NB. deaths for a period 100) (Infant Mortality Rate) Total number of newborn (NB. Discharges) Postoperative Number of deaths within 10 days of surgery 100 Death Rate Total number of patients operated on Autopsy Rates Newborn (NB) Number of autopsies on NB deaths 100 Autopsy Rate Total number of NB deaths Fetal Autopsy Rate Number of autopsies on intermediate and late fetal deaths 100 Total number of intermediate and late fetal deaths Gross Autopsy Rate Total inpatient autopsies for a period 100 Total inpatient deaths for the period Net Autopsy Rate Total inpatient autopsies for a period 100 Total inpatient deaths minus unautopsied coroner s or medical examiner s cases for the period Hospital Autopsy Rate Total hospital autopsies 100 (Adjusted) Number of deaths of hospital patients whose bodies are available for hospital autopsy The hospital patients whose bodies after death are available for hospital autopsy include inpatients, unless the bodies are removed from the hospital by legal authorities. However, in any such case, if the hospital pathologist or delegated physician of the medical staff performs an autopsy while acting as an agent for the coroner, the autopsy is included in the numerator and the death in the denominator.
372 Chapter XIII In addition, other hospital patients (including hospital home care patients, outpatients, and previous hospital patients who have died elsewhere) whose bodies have been made available for the performance of hospital autopsy, the autopsy is included in the numerator and the death in the denominator. Infection (Morbidity) Rates Total Hospital (Morbidity) Total number of hospital infections 100 Infection Rate Total number of discharges Nosocomial Number of hospital acquired infections 100 Infection Rate Total number of discharges (including deaths) Community-Acquired Number of community-acquired infections 100 Infection Rate Total number of discharges Postoperative Number of postoperative infections for a period Infection Rate (within 10 days postoperatively) 100 Total number of operations performed Other Rates Cesarean Section Total number of cesarean sections performed in a period 100 Rate Total number of deliveries in the period Consultation Rate Total number of consultations for a period 100 Total number of discharges for the period Delinquent Medical Total number of delinquent records 100 Record Rate Average number of discharges during a completion period Incomplete Medical Total number of incomplete records 100 Record Rate Total number of discharges during the completion period Percentage of Total number of Medicare discharges 100 Medicare Patients Total number of adult and children discharges Percentage of Medicare Total number of Medicare discharge days 100 Discharge Days Total number of discharge days for adults and children Readmission Rate Number of readmissions for a period 100 Number of total admissions (including readmissions) Generic Formulas Total number of times events actually happened 100 Percentage Rates Total number of times events could have happened Mean Median Mode Add all the available values and divide the sum by the total number of values involved. Example: Average length of stay or average daily inpatient census. The midpoint of an ordered series of numbers arranged in numerical order from highest to lowest or vice versa. The most frequently recurring value in a set of numbers is the mode.