Alpha level - Answers The level of Type I error that is deemed acceptable based on context in statistical
hypothesis testing. See Type I error.
Alternative hypothesis - Answers The complement of the null hypothesis that is to be tested using the
appropriate statistical test. This hypothesis typically requires some action to be taken.
Ambulatory payment classification (APC) - Answers The payment unit used in the hospital outpatient
prospective payment system (OPPS). The classification is a resource-based reimbursement system.
Analysis - Answers Reviewing and summarizing data for use in decision making.
Analysis of variance - Answers The statistical tool used to compare more than two population means.
The null hypothesis tests that all of the population means are equal.
Auditing - Answers "The performance of internal and external reviews (audits) to identify variations from
established baselines (for example, review of outpatient coding as compared with CMS outpatient
coding guidelines)."
Balanced design - Answers An experimental design where the number of subjects in each sample are the
same for all populations sampled. The term is relevant when performing an analysis of variance or a two
sample t-test.
Bell curve - Answers The shape of the normal distribution. The bell pealcs at the average and slopes
down on both sides symmetrically.
Binomial variable - Answers "A variable that talces only two values (such as yes or no; alive or dead). The
probability of a yes or no is constant across all of the subjects, and the outcome of each subject is
independent of the others."
Case Mix Index (CMI) - Answers "The average relative weight of all cases treated at a given facility or by
a given physician, which reflects the resource intensity or clinical severity of a specific group in relation
to the other groups in the classification system; calculated by dividing the sum of the weights of
diagnosis-related groups for patients discharged during a given period by the total number of patients
discharged."
Centers for Medicare and Medicaid Services (CMS) - Answers "The division of the Department of Health
and Human Services that is responsible for developing healthcare policy in the United States, for
administering the Medicare program and the federal portion of the Medicaid program, and maintaining
the procedure portion of the International Classification of Diseases, ninth revision, Clinical Modification
(ICD-9-CM) and International Classification of Diseases, tenth revision, Procedure Coding System (ICD-
10-PCS); called the Health Care Financing Administration (HCFA) prior to 2001."
, Chi squared test - Answers A statistical test that is used to test for relationships between categorical
variables. The null hypothesis for this test is that there is no association between the two variables.
Represented by the symbol X2 (where X is the Greek letter chi.)
Cluster random sampling - Answers "The population is divided into groups before the sample is selected.
The groups or clusters must be mutually exclusive and exhaustive. (That is, every unit in the population
is assigned to one and only one cluster.) Clusters are then randomly selected to make up the sample.
Cluster sampling may be performed as single-stage or two-stage."
Cluster Sampling - Answers Sampling where population is divided into groups (or clusters); groups are
then randomly selected to form sample
CMS-1500 - Answers "1. The universal insurance claim form developed and approved by the American
Medical Association (AMA) and the Centers for Medicare and Medicaid Services (CMS) that physicians
use to bill Medicare, Medicaid, and private insurers for professional services provided 2. A Medicare
claim form used to bill third-party payers for provider services, for example, physician office visits."
Coefficient of determination - Answers "A statistic that measures the amount of variance in a dependent
variable explained by one or more independent variables. If there is one independent variable, then this
value is the Pearson Correlation Coefficient squared."
Confidence interval - Answers An interval that is centered at the sample estimate of a population value
that may be calculated so that it has a preset probability of containing the population value.
Confidence level - Answers The probability that a confidence interval includes the true value of a
population statistic.
Contingency tables - Answers A useful method for displaying the relationship between two categorical
variables. Each category is displayed as rows or columns. The cells in the table represent the count of
subjects with each category attribute.
Convenience sampling - Answers A sampling technique where the selection of units from the population
is based on easy availability and/or accessibility.
Correlation - Answers A statistic that is used to describe the association or relationship between two
continuous variables.
Critical value - Answers The value that a test statistic must be larger than to conclude statistical
significance. The value is based on the alpha level of the test and the distribution of the test statistic if
the null hypothesis is true.
Current Procedural Terminology (CPT) - Answers "A comprehensive, descriptive list of terms and
associated numeric and alphanumeric codes used for reporting diagnostic and therapeutic procedures
and other medical services performed by physicians; published and updated annually by the American
Medical Association."