Before NACJD makes data available for distribution, a number of steps are taken. Staff at NACJD:
- Read the deposit form
- Review the electronic files
- Read the paper documents, if applicable
NACJD staff review deposited data and documentation for consistency and confidentiality by:
- Comparing the materials received to the descriptions of the materials described in the deposit form, project final report, and/or other correspondence with the depositor
- Comparing case and variable counts of data files to the stated case and variable counts in accompanying documentation
- Confirming that all necessary materials are present for a secondary analyst to use the data
No substantive changes will be made to data values (except possibly modifications for confidentiality) unless authorized by the original investigator. NACJD changes are documented in the processing notes provided in the codebook.
ICPSR staff is then able to develop a processing plan. This plan outlines:
- Confidentiality issues in the data and how it is to be released, e.g., restrictions and preservation
- The level of processing work and quality review necessary and/or desired to produce a quality data collection
- The structure of the final documentation files
NACJD staff may contact depositors once they have begun processing the data and documentation for public release. Since most of the questions about deposited data involve these types of data and documentation questions, researchers can greatly streamline the process by performing similar checks on the data and documentation prior to submission. Resolving any data and documentation problems is easier when the project files are still on the investigator's computer system and before project materials are boxed and stored.
Creation of Study Descriptions
NACJD staff will prepare a study description based on information provided in the project final report, deposit form, or other comparable description. These descriptions follow a strict format to ensure that standard information is recorded for each study. The format consists of named fields into which NACJD staff enter corresponding information about the study.
Completed descriptions ultimately reside in an online database, which is searchable and provides a future user with a general overview of the study to help determine the suitability of the data collection for the user's research purpose. The study description along with the codebooks and associated instruments also distributed with the data are intended to provide the user with enough information about the study to enable secondary analyses by the user without the need to contact the original investigator.
Study descriptions contain at least:
- ICPSR Classification
- ICPSR Study Number
- Study Title
- Principal Investigators
- Extent of Collection
- Extent of Processing
- Time Period
- Collection Note
- Case and Variable Information for each Data File
Study descriptions may also include:
- Series Information
- Data Type
- Date of Ingest
- Funding Agency
- Grant Number
- Source of Data
- Format of Data
- Collection Changes
Processing and Quality Review
ICPSR strives to release data in as timely a manner as possible. Sometimes these processes take longer than anticipated. However, ICPSR believes these important archival operations should be performed carefully, with attention to detail.
The amount of processing work performed on data collections deposited with NACJD varies greatly and depends on the condition of the files upon arrival and the resources available to perform processing work. All data collections undergo a series of mandatory reviews prior to release. In particular, NACJD staff performs the following activities for most data collections.
- Evaluate the data collection for completeness, suitability for public release, and readiness for use
- Determine whether any problems of confidentiality exist arising either from direct or indirect identification and remove or recode sensitive information accordingly
- Check the data against the documentation regarding expected case and variable counts as well as the presence of out-of-range values, undocumented codes, and other data inconsistencies
- Consult with the depositor, when necessary, to remedy any problems uncovered during the review of the data
- Standardize and/or label missing data codes
- Restructure the data and documentation files as necessary to promote usability and achieve more efficient transmission and storage
- Create data files in multiple distribution formats to facilitate analysis: SPSS system, SAS transport, and Stata system files as well as ASCII data with SPSS, SAS, and Stata setup files
- Produce all documentation in Portable Document Format (PDF) files; convert original paper documentation into PDF
- Prepare finding aids, including searchable study descriptions and bibliographic citations, to assist in locating the collection within the archive
- Back up and store both the original data and the processed data at external sites
If resources permit, the staff may undertake further processing steps and data enhancements:
- Check for consistency of survey responses and skip patterns
- Prepare the data for online analysis
Once all processing work and quality reviews have been completed, the data collection is ready for release to the research community through the NACJD website or through restricted data access or delayed dissemination procedures described elsewhere.
The release of the data is announced on the ICPSR and NACJD websites and via the ICPSR Recent Updates and Additions email notification service.
Depositors should instruct researchers interested in the data and/or files they deposited to visit the NACJD website, where they will be able to read the study description, browse the accompanying documentation, and download the files. NACJD staff provide technical assistance for data distributed by NACJD.