DATA MANAGEMENT AND STATISTICAL ANALYSIS CORE

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A. OBJECTIVE Consultation on study design: The Data Management and Statistical Analysis (DMSA) Core provides consultation to investigators who are designing new studies. We prefer to become involved in the initial development of studies to assist in study design. We assist by providing feedback on the degree to which the proposed design can address the research questions with the proposed sample. We conduct power analyses to identify optimal study designs. We assist the investigator in developing the analysis plan by making recommendations regarding statistical methods to ensure that their analysis plan provides the most appropriate testing of research questions with the proposed instruments and samples. Finally, we can assist UNC DDRC investigators by providing feedback on instruments. We have over 25 years of experience in processing and analyzing assessments of children's social and cognitive skills and of parent characteristics and responsiveness with the child and can make recommendations regarding the psychometric properties of most widely used measures. Based on our experience, we can inform investigators whether the instruments they selected were successful (or unsuccessful) in previous studies with specific populations. For example, we found that it is extremely difficult to use some standardized cognitive screening instruments with children with moderate or severe mental retardation due to failure to obtain basal scores with most of those children and that some widely used teacher and parent questionnaires have questionable internal consistencies when used with individuals without posthigh school education. Consultation on data management: The application analyst provides consultation regarding data management to all UNC DDRC investigators. Careful implementation of quality assurance practices and documentation are necessary for maintaining the integrity of data as they are entered into databases. We meet with project staff to assist them in implementing recommended practices such as: ¿ Creating tracking logs to document the process of all data from collection through processing ¿ Creating data entry practices such as development of screens in which invalid or out-of-range values are tagged and data entry by two independent keyers and discrepancies are resolved by reviewing forms ¿ Creating carefully documented database files, including computerized error detection procedures (valid value/range, consistency), annotated code books and documents of decision rules for resolving errors and scoring data ¿ Consultation on instrument selection and the availability of computerized scoring algorithms for those instruments Consultation on statistical analysis: The statisticians in the Core provide statistical consultation to all UNC DDRC investigators. We are available to consult with all UNC DDRC regarding the analysis plans for funded UNC DDRC projects. This consultation can involve designing analysis plans and assisting UNC DDRC project staff in implementing those analyses and in interpreting results. Core statisticians have extensive experience with most methodologies used by UNC DDRC projects, including: Data reduction Regression, analysis of variance and linear models Logistic regression and survival analysis Growth curve analyses using linear and nonlinear methodologies Structural equation models Cluster analysis and discrimination methods useful in analyzing data from gene micro-array studies Analysis of differential expression or similar analysis on a variety of-omics platforms Analysis of genetic association data Model-based and spatial methods used to analyze imaging data Additional bioinformatics issues The statisticians and bioinformatics personnel assist UNC DDRC investigators by providing bioinformatics/ biostatistics support for basic experimental design and database management, guidance in the analysis of data, and data mining. Details of specific approaches are given further below. Core personnel provide assistance in interfacing with UNC genomics core microarray facilities, which primarily use Agilent and Affymetrix technologies. Genotyping core facilities have been greatly expanded in the last year, and are primarily based on the Illumina platform. DDRC researchers occasionally require assistance in interpreting basic file formats for their work. Core personnel can also aid in data sharing and uploading data to public repositories. A portion of internal data sharing of microarray data is mainly accomplished via the UNC Microarray Database, which has a log-in system and a common set of data formats. Training: The Core will continue providing seminars and short-courses to UNC DDRC investigators and project staff. We have offered one to two seminars per year on topics related to data management and statistical analysis as part of the UNC DDRC monthly investigators' meeting and plan to continue this. In addition, we planned to offer one short-course per year to project staff and interested investigators to provide an overview on data management practices and complex statistical methods, but found that working collaboratively with investigators using their project data was more effective. Unfortunately, investigators were too busy to participate in short-courses, whereas they found that we were quite effective in training when the training involved direct application of methods to their data. In these informal trainings, we consult with investigator regarding study design, data management, and data analysis. These consultations often introduce UNC DDRC investigators and staff to new practices and methodologies. We try to ensure that each investigator or staff member understands the basic concepts involved in and when these methods are appropriate for all practices we recommend. Similar training occurs for bioinformatics consultation and collaborations. Dr. Wright has given periodic lectures about statistical techniques for analysis of genetic data. UNC Center for Bioinformatics (http://bioinformatics.unc.edu) is an extremely valuable resource, and provides first-line basic training at no charge to UNC investigators, staff, and students. The Center for Bioinformatics Center has dedicated facilities, or can travel to an investigator's lab using laptop computers. Additionally the Center for Bioinformatics maintains numerous site licenses for bioinformatics analysis software (e.g., Genespring). Additional training of UNC investigators occurs in one-on-one consultation with Core statisticians. Hiring, training and supervision of project data managers and statisticians: We meet with interested UNC DDRC investigators to determine the extent to which they would like assistance with data management and statistical analysis. Consulting is available to all projects, but many investigators prefer to have the Core provide all data management and statistical support for their project. The Core is located within the Design and Statistical Computing Unit (DSCU) at the Frank Porter Graham Child Development Institute, and in the UNC Department of Biostatistics. The DSCU consists of 20 programmers and six statisticians. The Core is able to assign these programmers and statisticians to work on UNC DDRC projects if those projects pay for the time those individuals spend on their projects when requested services go beyond those supported by the Core. The easy availability of these programmers and statisticians for this expanded service provision is convenient for investigators and ensures that consistent high quality is maintained. We have been able to provide these services by using UNC DDRC funds for the recruiting, training, and supervision of DSCU staff who provide the actual data management and statistical analysis for the UNC DDRC projects. Investigators who request that our unit provide direct data management or statistical analysis beyond the consulting role described above that is considered part of the Core support must fund that effort from their grants. These DSCU staff members become part of the research team, and are hired, trained, and supervised by the Core personnel. The Core is able to recruit talented individuals and train them in professional data management and statistical methodologies. The Core supervises these individuals to ensure that quality assurance practices are maintained in data management and that appropriate and powerful statistical methods are used to analyze data. This is quite beneficial to projects with extensive behavioral assessments, especially since almost all projects are too small to need a full-time data manager or statistician and would be unable to recruit professionally trained individuals to work on their projects. Assistance with data management and analysis: Direct services are provided to assist investigators seeking additional funding. Core programmers and statisticians provide direct assistance to DDRC investigators as they develop new UNC DDRC projects or to help them maintain longitudinal projects when those projects are without other support. We assist investigators who conduct pilot studies by processing and analyzing those data. Core personnel also have provided data management and statistical analysis assistance to DDRC projects that are seeking renewal and may be without support at that time. This assistance has been especially valuable for longitudinal projects because data collection usually extends to the end of the funding cycle. With our assistance, the renewal proposal can include results from work funded by the last grant. Unfortunately, we cannot provide direct services to most projects due to the number of projects and the large amount of data collected by almost all projects. Our goal is to ensure that all investigators can be assisted when writing proposals, all projects can consult with us regarding data management or analysis, and any investigator can use our professional data managers and statisticians as part of their research team if the project pays for those direct services.