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Techniques for Optimizing PDFs for Search Engines

Part 1: Optimizing PDFs for EERE's internal search engine

Title field

  • Tips:
    • Use the title as it appears in the document.
    • If you have to cut the title short, end the title with complete words, not in the middle of words.

  • Purpose/notes:
    • Titles appear as the caption for PDFs in search results.
    • Titles are searchable in the search engine.
    • Words in titles contribute greatly to ranking in the search engine.
    • Titles and summaries are the most important fields in document information and in the search engine.

Subject field (document summary)

  • Size:
    • Summaries must be at least 71 characters and should not exceed 200 characters.
    • Summaries with less than 71 characters will not display.
      • If there is no summary to display, the search engine will use the first 200 characters of text it finds on the page.
        • Fonts, text columns, and other factors frequently cause the search engine's summary to be scrambled, so always create a summary.

  • Tips:
    • Always provide a summary (see previous sentence for more information).
    • Use the summary to describe the content of the document and to give users an idea of what the document is about.
      • Include terms used in the document — this enhances the ranking in search results.
      • Put the most important information in the first 150 characters.
        • This is the field limit for some Web-wide search engines.
      • Keep it simple.
      • Make each description unique.
      • To save space, you do not have to use complete sentences:
        • For example,
          • Provides information on...
          • Includes...
          • Information on...
      • Save time by using a template for fact sheets, series, or other documents that are similar in nature:
        • This factsheet provides information on ...
        • EREC factsheet on ...

  • If you don't have the money or time to prepare descriptions:
    • Use the first couple of complete sentences from the first page of the document,
    • Use the first couple of descriptive sentences if the first few sentences don't describe the content, or
    • Use the heading if it is more descriptive than anything else.

  • Purpose/notes:
    • This field is misnamed; it is actually the summary field.
    • Information in this field appears as the PDF summary in search results.
    • Words in summaries contribute to ranking in the search engine.
    • Titles and summaries are the most important fields in document information and in the search engine.

Author field

  • Tips:
    • Use only personal names.
      • Do not include the author's affiliation.
      • Do not include any organization names.
    • List only the authors whose names appear in the document.
    • Use names as they appear in the document.
    • List elements in this order: first name, middle initial (if provided), last name:
      • Larry Kazmerski (not Kazmerski, Larry)
    • Use semicolons to separate names:
      • Robert Smith ; Tom Jones
    • When in doubt, leave this field blank.

  • Purpose/notes:
    • This field lists authors whose names are provided in the document.
    • Authors are searchable in the search engine using author: searches.
    • Authors do not display in search results.

Keyword field

  • Tips:
    • Use single terms or phrases
      • metalcasting
      • horizontal axis wind turbines.
    • Use only terms and phrases that appear in the document.
    • Use lower case:
      • wind turbines (not Wind Turbines)
    • Use plural forms of words:
      • wind turbines (not wind turbine)
    • Separate terms with commas:
      • transpired solar walls, commercial buildings
    • Keep it simple:
      • Use only four or five keywords or phrases to describe the main subjects of the document.
      • Exceptions are scanned documents, which don't have text that can be indexed by the search engine.
      • Incorrect or bad keywords are worse than no keywords, and will skew search results.
      • If you do not have the time or money to supply meaningful, concise keywords, leave this field blank.

  • Purpose/notes:
    • This field lists the main subjects covered in the document.
    • Keywords are searchable in the search engine.
    • Keywords do not display in search results.

Part 2: Optimizing PDFs for Web-wide search engines

  • Major Web-wide search engines such as Google, Yahoo, and MSN Windows Live are indexing PDFs.
    • All of them display our PDF titles in search results.
    • None of them display our PDF summaries in search results.

  • The optimizing techniques listed for EERE's internal search engine are valid for Web-wide search engines because:
    • Web-wide search engines display our PDF titles.
    • Web-wide search engines may display our PDF summaries in the future.

For more information, contact the Search Engine Specialist.