Long-Term Pavement Performance Compliance With Department of Transportation Information Dissemination Quality Guidelines
CHAPTER 4. Dissemination of Information
Dissemination of information is one of the stated objectives of the LTPP program. The primary focus of the program is to provide a macro release of raw data for use by scientists, engineers, and researchers for engineering based analysis. While published summaries and microdata releases are not the primary dissemination mechanism, a limited amount of data have been distributed in this fashion. The macrodata release includes documentation of data sources and, where possible, accuracy indicators. In accordance with the IDQG, all disseminated data are required to receive some type of review prior to release.
Publications and Disseminated Summaries of Data
Since a primary objective of the LTPP program is to provide raw data for analysis and interpretation by researchers, dissemination of information in printed publications containing statistical summaries is not the primary dissemination mechanism.
- The published results of FHWA-sponsored data analysis of LTPP data contain statistical summaries and data interpretation relevant to the subject.
- All published reports are subjected to the FHWA publication process which includes editorial review for conformance with FHWA publication standards, inclusion of a report documentation page, which lists all pertinent meta information about the authors, contact information for the authors, contract reference, time period the work was performed, abstract, key words, and other metadata.
- Many of the LTPP publications predate the introduction of Section 508 of the Americans with Disabilities Act by more than 10 years; documents published after the act's implementation date have been formatted in conformance and are reviewed by individuals trained in DOT Section 508 compliance standards.
- References in publications are documented following FHWA publication guidelines. All documents are dated.
- Data analysis documents, which contain estimates and projections, are required to contain a description of the analysis methodology. These documents receive both an internal and independent external review by knowledgeable experts on the subject prior to publication.
- All publications contain contact information for the report author, FHWA Contract Officer's Technical Representative, and other citations as required on the FHWA's Technical Report Documentation Page (Form DOT F 1700).
- Due to the breadth of the LTPP program, a number of unpublished documents on specialty topics have been made available to the public. Due to practical budget constraints, these documents do not receive the same level of scrutiny or review as published documents. Although many of these documents do not receive a formal peer review, they are reviewed internally prior to release.
Although the primary thrust of the LTPP program are macrodata releases, the following microdata releases are used to encourage participation in the program and serve targeted sectors of the transportation research community:
- A microrelease of data is used for preparation of information packages intended to encourage continued highway agency voluntary participation in the program. These packages present data extracted from the database which show time history and pavement performance trends on the agency's test sections. The extracted data used in these releases have been subjected to all data QC and assurance checks.
- In order to better serve users of analysis software that require a specific data format, LTPP has provided microdata releases in standardized formats. These data have undergone data quality checks prior to release. Examples include the following:
- FWD time history data that are not included in the database, in the native format produced by the device.
- Profile data in an industry developed data interchange format.
- Raw traffic data measurements are provided in the FHWA standard "card" formats.
- LTPP offers a custom data extraction service. This service is designed to provide data to those interested in pursuit of analysis of a specific topic.
Source and Accuracy Statements
While LTPP does not have formal publication-named Source and Accuracy Statements (S&As), it has developed a vast array of documents which contain the content covered in this part of the guidelines.
- In many cases, data sources are contained in code fields in each record in the database. For example, materials testing laboratories are assigned an identifying code that is contained in each database record containing data from that laboratory.
- Where possible, descriptive statistical information is contained in the database to permit data users to quantify variability and uncertainty in key measured data elements.
- A data user reference guide, distributed with data releases, contains documentation on data sources on a module and table basis. This document is updated with each data release to reflect changes in data sources and collection methods.
- Topical data collection and data processing guides have been prepared by LTPP. Appendix A contains a list of this documentation. Updated data collection and data processing guides are documented by issuance of formal program directives.
LTPP has collected data that could be used to better evaluate data accuracy. Due to funding constraints, these data and reports have not been distributed on a published basis. Some of the information collected by LTPP that could potentially aid a user in assessing the accuracy of the reported measurements are as follows:
- Reference and relative calibration results on FWD geophones are not contained in the database. The electronic files created as a part of this function are considered part of the Ancillary Information Management System (AIMS). Efforts are currently underway to store these data in a central location and populate a metadata database on the contents of these files.
- The reports documenting the side-by-side comparison of FWD and profile equipment operated by LTPP have not been formally published. Through the TRB peer review process, data users have indicated that although these detailed measurement information could theoretically be valuable, the limited amount of research funding in the United States
would create too many expenditures for the limited use of the data.
All formal data disseminated by the LTPP program undergo some type of review prior to release. The type and extent of the review depends on the subject matter being released. LTPP is developing an information category for dissemination that does not receive a "formal" review prior to dissemination.
The following types of formal predissemination reviews have been conducted by LTPP:
- The contents of the database are reviewed by experts and specialists on the central Technical Support Services Contractor (TSSC) staff prior to release. These review staff members are not directly involved with data collection or analysis. Data collection is the responsibility of four regional data collection contractors who collect data, process data, and review data prior to each upload to the national database. At the national level, data from the four regions are combined into a single database. Prior to each release of the database, the TSSC staff members perform a predissemination review of the database contents, notify the regional data collection contractors on needed corrections, and review corrections received prior to the release. Known data problems not corrected prior to release are documented using the Data Analysis Operation Feedback Report process.
- Paper publications are subjected to a variety of predissemination reviews depending on subject content.
- All published paper documents are reviewed by editors employed or contracted by the FHWA TFHRC publication staff. These editors are specialists trained in style and visual information content of FHWA publication standards.
- Program promotional material and status reports are reviewed by FHWA LTPP staff and contractors who did not actively participate in preparation of the draft document.
- Research reports containing engineering and statistical analyses receive an external and internal peer review in addition to the other predissemination reviews previously mentioned. The peer reviews are conducted by a diverse group including voluntary experts from the TRB ETG on data analysis, paid experts from the LTPP TSSC, and, most importantly, engineering staff from the regional data collection contractors. This rigorous peer review process includes knowledgeable individuals from outside the program who represent program stakeholders and academia; a paid staff of researchers not involved with the performance of the data analysis work, but who have unique knowledge of the LTPP program and have resources available to independently check reported results; and, most importantly, reviewers who collected the data and possess knowledge on its proper analytical interpretation.
- Report reviewers on the TRB ETGs are required to report prior DOT technical/policy positions on issues related to LTPP as part of their conflict-of-interest disclosures required by the National Academy of Sciences before being appointed.
- LTPP contractors are required by the Federal Acquisition Regulation (FAR) guidelines to report conflict-of-interest concerns in their proposals.
- The peer review process has resulted in nonpublication of program-funded analysis reports.
- After the passage of Section 508 of the Americans with Disabilities Act, all disseminations of information via electronic media have been reviewed by specialists who have received training on this legislation. All LTPP contractors responsible for managing Web pages containing LTPP program information have Section 508 compliance clauses included in their contracts. All LTPP-sponsored Web pages have been reviewed by LTPP staff for compliance conformance. As a long-term program, LTPP has been hampered by the lack of effective FHWA guidelines on implementation of this policy. To date, LTPP electronic documents have not been challenged by persons with disabilities for nonconformance with the Section 508 requirements.
- Data products were disseminated by LTPP prior to enactment of Section 508 of the Americans with Disabilities Act. Since these data products can no longer be controlled by the program, documentation has been published that these data products are no longer supported by the program, and concerned data users should use current data products or contact LTPP concerning accessibility accommodation for the disabled. To date, LTPP has not received such a request.
LTPP had developed plans for a system that allows dissemination of raw data that has not undergone a formal predissemination review. While the bulk of these data are contained in the database, the data included in this category are classified as objects in database terminology. Most of these electronic objects consist of electronic picture formats, but, on the advice of the external peer reviewers, many are the unedited electronic files from data collection devices. This allows a data user the opportunity to evaluate LTPP data processing and quality systems. At the heart of the process was the creation of a metadata database. The concept that was previously developed is that the metadata about an object contain adequate information to describe the format, content, quality review level, and nature of the data included in this module. The LTPP metadata database was planned as an electronic library based on the Dublin Core Standard and in concert with electronic library standards currently under development by the U.S. National Archives, Library of Congress, and internal FHWA publications staff. Due to budget cuts, development of the formal metadata database has been curtailed to documents indexed by the FHWA library staff.