PREPRINT: generally a manuscript designed to be circulated among colleques for review, though they may end up being more formally printed or reviewed by an institution or even indexed and distributed by a clearinghouse.
CORPORATE "PROPOSAL TYPE" REPORT: for example, a corporate proposal to an agency when applying for a grant. These are usually proprietary and not publicly available.
INSTITUTIONAL REPORT: such as the annual or progress reports of government agencies, foundations, corporations, societies, and laboratories. These reports generally give a good overview and may include bibliographies.
CONTRACT "PROGRESS REPORT": the largest class of technical reports in circulation, produced either monthly or quarterly as required by the terms of the research contract. The information included in the progress report may or may not be contained in the final report for the contract.
CONTRACT "FINAL REPORT": probably the most valuable technical report, generally providing a good overview of the research performed under contract, with some editorial review before release. There is a great variety in the format, distribution, and indexing of these reports.
"SEPARATE" TOPICAL TECHNICAL REPORT: closest to the journal article in terms of style and type. Many originate with either the sponsor or staff working on a project, and may be released as research memoranda, research notes, or technical memoranda. These reports often appear later in journals in an abbreviated form.
"BOOK" IN REPORT FORM: survey type materials, such as reviews and state-of-the-art reports. These appear earlier than the commercial book and at lower cost.
COMMITTEE-TYPE REPORT: the findings and conclusions of research by scientific advisory groups. Most of these reports include bibliographic annotations, but their style varies greatly. They often have poor distribution and are usually not adequately described in references. Series designations, for example, are often ignored in descriptions of these reports.