Data Collection and Management for Clinical Research
Michael A. Kohn, MD, MPP31 August 2010
Topics
Data Tables: rows = records, columns = fields
Data Dictionary: a table of data about your data table(s)
On-screen data collection forms
Data Tables
Study data are stored in one or more data tables in which –
Rows = Records = EntitiesColumns = Fields =
Attributes
Interview Data
Exam Data
Questionnaire Data
Outcomes on same form as predictors
Demonstration: Creating a Data Table
Label columns and enter rows of data in datasheet view
Demonstration: Data Dictionary
Table design view:•field (=column) names, •data types, •definitions, •validation rules
Demonstration: Data Validation
Disallowed values
Duplicate primary keys
(SubjectDemo)
(Subject)
Demonstration: Same Table in Excel, Stata
Excel Stata Etc
Rows = Records = EntitiesColumns = Fields =
AttributesAccess and Stata have a special row at the top for column headings (=field names); Excel just uses the first row.
Data Collection Forms
Nothing focuses the study like the need to develop a data collection form
Forces you to get concrete about your predictors, outcomes, and other measurements.
Planning Data Collection and ManagementSearch the internet and ask other researchers for
already developed data collection forms.Draft your data collection form.Test your data collection form with dummy subjects
and, even better, with real (de-identified) study subjects.
Enter your test data into a data table with rows corresponding to subjects and columns corresponding to data elements. (Use Excel, Access, Stata, or even Word.)
Create a data dictionary.Decide who will collect the data, and when/how the
data will be collected.
NHAMCS
nhamcs100-ED_2007.pdf
From Paper Data Forms to Data Table(s)*
Transcription directly into the table(s) Transcription via an online (screen) form Scanning using OMR software
*Best option: Don’t use paper data collection forms at all
Creating On-Screen Forms
Microsoft Access Filemaker Pro REDCap QuesGen (today) SurveyMonkey Others
On-Screen Data Collection Forms
Demonstrate the QuesGen web form This is easy to do in SurveyMonkey
and REDCap too Access and FilmakerPro can both
create nice on-screen forms, but not as easy to make available and secure via the Internet
Clinical research studies consistently under-plan and under-budget for data management.
One FTE research assistant, including benefits, will cost your study ~$100k/year; you should be willing to spend one tenth as much for consulting on your database system.
Don’t leave data checking, validation, and cleaning for the biostatistician a) it will be too late; b) biostatisticians do not view data cleaning as part of their job.
Assignment?
Write a one-page data management section for your research study protocol.
Draft your data collection forms!