Terms Related to Data Collection
In addition to understanding what is measured, it is important to understand how data on these measures are collected. The terms defined below are used throughout this report; the specific methods of data collection are examined in greater detail in the following chapter.
Measures are specific data collection items within a survey/interview or administrative record system, including scales, numerators, and denominators, that serve to score survey results, medical records data, administrative data, and similar data sources. They involve such questions as: “Would you rate your child’s overall health as excellent, very good, good, fair, or poor?,” “What is the birth weight of U.S. infants?,” “What is the average age, weight, or height of children served?,” “Have you [an adolescent] ever used marijuana?,” “Do you smoke cigarettes?,” “Have you ever engaged in sexual intercourse?,” and “How often do you take aspirin or medications like Tylenol for headache or other physical pain?”
Indicators are a collection of individual quality measures, consisting of a denominator and a numerator, that suggest a trend or pattern of health conditions, behaviors, or influences. Indicators of mental health status, for example, may consist of several individual measures of selected disorders, such as depression, attention-deficit disorder, and mental retardation.
Indexes are composites of indicators that are weighted to reflect assumptions about the relative value of selected indicators. One such example is body mass index (BMI), an index calculated on the basis of an individual’s weight and height (and for children, gender and age) and used in the clinical assessment of obesity and overweight. Another example is the Consumer Price Index (CPI), which represents the total cost of a market basket of goods and services purchased by households at a point in time. Inflation is defined as a change in the CPI and is used by government, business, labor, and private citizens for many purposes. Some scholars have attempted to develop a Child Well-being Index (CWI) as a similar standard for assessing the general status (including health) of children over selected years. The CWI concept is based on a composite of indicators of well-being, including “economic well-being, safe/risky behavior, social relationships, emotional/spiritual well-being, community engagement, educational attainment …. and health” (Land and FCD, 2010, p. 3).
Data systems are the collection of measures (e.g., surveys, indicators, and other reporting tools) that are used to examine the quality of child and adolescent health and health services. A data system may consist of several federally sponsored surveys, such as the National Immunization Survey (NCHS, 2011c), the National Health Interview Survey (NCHS, 2011b), and the Survey of Children with Special Health Care Needs (NCHS, 2009b). Data systems may require the linkage of several indicators or data sets to examine specific questions about the impact of children’s health care quality on selected areas of functioning, such as: “What do we know about the impact of the quality of asthma care on the educational outcomes of school-aged children with asthma?”