Governement technical reports typically publish the results of research projects conducted for government agencies. They are usually produced in response to specific information needs with research either 1) conducted "in-house" by state or federal research labs, or 2) contracted out to universities, consulting firms, research institutes, or private industry.
Progress and final reports typically are used directly by the sponsoring agency with limited distribution beyond the organization. As a result technical report literature is sometimes called "gray literature" because of its difficulty to identify and acquire.
The format of technical reports is more flexible in organization and tends to contain more of the scientific data collected. Research first reported in a technical report may be reworked and published in other "primary" literature formats.