STATEMENT OF THE PROBLEM AND STUDY DESIGN Lu Ann Aday, Ph.D. The University of Texas School of Public Health

TYPE OF DESIGN: Observational – Cross-Sectional (One-Group) GROUPS No. of groups: 1 Criteria for selection: Population of interest TIME PERIODS No. of time periods: 1 Reference periods: Present (and recall of past)

TYPE OF DESIGN: Observational – Group-Comparison (Case-control) GROUPS No. of groups: 2+ Criteria for selection: Population subgroups with and without characteristic of interest TIME PERIODS No. of time periods: 1 Reference periods: Present and recall of past

TYPE OF DESIGN: Observational – Longitudinal (Prospective) GROUPS No. of groups: 1 or 2+ Criteria for selection: Population or subgroups that are and are not likely to develop characteristic of interest TIME PERIODS No. of time periods: 2+ Reference periods: Present and future

TYPE OF DESIGN: Experimental – “True” Experiment (Randomized Clinical Trial) GROUPS No. of groups: 2+ Criteria for selection: Randomly determined subgroups of population TIME PERIODS No. of time periods: 2+ Reference periods: Present and future

DESIGN DIMENSIONS HEALTH SURVEY EXAMPLES UNICEF MULTIPLE INDICATOR CLUSTER SURVEYS (MICS) CALIFORNIA HEALTH INTERVIEW SURVEY (CHIS) NATIONAL DENTAL MALPRACTICE SURVEY (NDMS) Study Objectives 1. To estimate and monitor World Summit for Children and related World Fit for the Millennium Development Goals (MDGs) indicators of child survival and development for children and mothers in participating countries. 2. To compare the indicators over time, as well as across countries. 1. To provide statewide estimates for the population of the State of California overall and local-level estimates for most counties in the State of California on a variety of public health topics, e.g., health status, health care access, insurance coverage. 2. To compare estimates across local areas and between larger racial/ ethnic groups, and selected smaller ethnic groups. 1. To estimate dental malpractice insurance experience in a representative sample of U.S. dentists in To test hypotheses regarding the practice characteristics that are predictive of dental malpractice insurance experience. Study Designs Descriptive longitudinal, comparative national surveys conducted in 1995, 2000, & 2005 in participating countries Descriptive longitudinal, comparative state & local surveys conducted on a biennial basis, beginning in 2001, in the State of California Analytical cross-sectional national survey of U.S. dentists, conducted in 1991 Research Questions What? World Summit for Children & MDG indicators of child survival & development health status, chronic conditions, health behaviors, health care access, insurance coverage, etc. malpractice insurance experience & practice characteristics Who? children & mothersstate & county populationsdentists Where? participating countriesState of CaliforniaU.S. When? 1995, 2000, , 2003, Why? -- To test hypotheses regarding the practice characteristics that are predictive of dental malpractice insurance experience.

SAMPLE OBJECTIVE: Objective 1 1. TO ESTIMATE dental malpractice insurance experience in a representative sample of dentists in the U.S. in 1991.

SAMPLE OBJECTIVE: Cross-Sectional, Descriptive Design OBJECTIVEELEMENTS TO ESTIMATESTATISTICAL PROCEDURES: Univariate, e.g., frequencies, mode, median, mean dental malpractice insurance experienceWHAT? in a representative sample of dentistsWHO? in the U.S.WHERE? in 1991.WHEN?

SAMPLE OBJECTIVE: Objective 2 2. TO COMPARE dental malpractice insurance experience by the dentist’s demographic characteristics.

SAMPLE OBJECTIVE: Group-Comparison, Descriptive Design OBJECTIVEELEMENTS TO COMPARESTATISTICAL PROCEDURES: Bivariate, e.g., chi-square, t-test, ANOVA, correlations dental malpractice insurance experienceWHAT? (dependent variable) by the dentist’s demographic characteristics. WHO? (one independent variable)

SAMPLE OBJECTIVE: Objective 3 3. TO ANALYZE the relative importance of doctor-patient communication, practice characteristics, practice finances, and dentist’s demographic characteristics in predicting dental malpractice insurance experience.

SAMPLE OBJECTIVE: Objective 3—Hypothesis Doctor-patient communication is more important than practice characteristics, practice finances, and dentist’s demographic characteristics in predicting dental malpractice insurance experience.

SAMPLE OBJECTIVE: Cross-Sectional, Analytical Design OBJECTIVEELEMENTS TO ANALYZE the relative importance ofSTATISTICAL PROCEDURES: Multivariate, e.g., linear regression, logistic regression doctor-patient communication practice characteristics practice finances, and dentist’s demographic characteristics in predicting WHO? (two or more independent/control variables) WHY? (hypothesis re results) dental malpractice insurance experience.WHAT? (dependent variable)

MEASUREMENT MATRIX : National Dental Malpractice Survey (Aday & Cornelius, 2006, Table 15.1) QUESTIONCONCEPTLEVELOBJECTIVE 3 Doctor-patient communication: characteristics of unsatisfactory patient encounters (Likert scale) ordinal (interval) 3 10 Practice characteristics: avg. office waiting time for patient ordinal 3 28 Practice finances: % patients with insurance coverage interval 3 35 Malpractice insurance: no. of complaints ordinal 1, 2, 3 54 Demographics: gendernominal 2, 3

SURVEY ERRORS: Matching the Survey Design to Survey Objectives Systematic ErrorsVariable Errors Poor internal validity Poor external validity Design specification ambiguity Solutions to errors Use randomization, matching, or statistical controls to rule out other factors that may account for relationships between variables. Clearly specify where, with whom and when the survey will be done in stating the study objectives and design the sample frame and survey sampling procedures accordingly. Clearly specify the study objectives and related concepts to be measured in the survey, particularly in relationship to the underlying study design and data analysis plan for the study.