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4.4.2 Search Strategy Considerations

Date Published

Research into search theory recommends starting the search narrowly in the area that you most expect to find relevant art. A series of focussed searches is normally more effective than a single large search. If needed, you can broaden your search in an iterative manner by reflecting on the art found from earlier searches, for example, which keywords worked well, did any particular classification symbols produce useful art?

The adage ‘search the inventive concept as embodied and report on the claims’ should be followed, but the examiner should be prepared to search more broadly in order to identify art relevant to the claims per se. Where necessary, search analogous fields for citations that might be suitable for the purpose claimed, but which don’t match the embodiments.

The following presents a series of questions that if addressed will help guide the examiner and 3PT members when formulating their search strategies:

Have the claims been construed properly?

What search areas/databases would reasonably be considered to contain relevant prior art?

  • What sources of information seem to be the most fruitful for getting the information required? This will often be technology specific;
  • is the technology such that I need to search non-patent Literature NPL (see Non-Patent Literature)? NPL could range from product catalogues for simpler inventions to journals, conference proceedings and technical reports for more advanced technologies;
  • is the technology widespread and something found on a shelf and would be found using a Google image search or encompassed in an industry standard?;
  • are the keywords I’m thinking of using the type of terms used in an abstract, or would full text be more appropriate?; and
  • where the examiner has difficulty in deciding whether a particular area should be searched, or in identifying any relevant IPC/CPC subgroups in which to conduct a search, he or she should:
    • seek advice from a senior examiner and/or examiners who have had experience in the possible search areas;
    • use a tool such as Espacenet to identify classification symbols accorded to similar subject matter by other countries; and
    • conduct trial searches in possible areas to establish the relevance of the area to the search required (see also Preliminary Search).

Do the selected search areas/databases meet the PCT minimum requirements? (For PCT applications only)

  • In most cases, an EPOQUE search of WPIAP and EPODOC should be considered standard practice in order to cover patent literature. Certain technologies may have alternate standard databases (for example, Chemical Abstracts/Registry, Genomequest etc.). See also 4.4.3 Search Area; and
  • free databases are highly useful and can provide results quickly but may not meet the PCT minimum requirements on their own.

See also Minimum Documentation.

Are the selected search terms, classifications and search statement combinations relevant?

  • Technical language and terminology can differ between countries and publication types (for example, patents vs. journal articles). Employ controlled language searching where possible. The use of classification symbols and controlled language/terms not only increases precision and recall but is also preferable to the use of broad keywords/synonyms which may not specifically target the technical feature and/or account for differences in language;
  • the search terms/IPC/CPC should limit the search to the technical features of the invention/inventive concept;
  • the search should not be unnecessarily limited to insubstantial features not related to the inventive concept;
  • care should be taken with truncation and synonyms such to prevent retrieval of non-specific results. Similar care should be taken when combining search statements;
  • make use of the CPC – more often than not there is a greater breakdown of classification and you could find yourself only needing to search a single CPC symbol;
  • when relying on keywords, select the most likely keywords for your search. Only broaden the range of synonyms if you need to and in subsequent searches. By searching iteratively you can work out which keywords and a combination of terms is most effective;
  • are the keywords so generic that I am better off considering picture searching?;
  • constantly review the choice of search terms and classification symbols as you search. If you find useful terms/symbols that you did not originally use then consider repeating the search; and
  • refrain from using keywords that are implicit in a device and would not feature in an abstract.

Are there alternative approaches to selecting search terms and classification symbols. Consider:

  • searching for the benefit that the device offers;
  • searching for the action or use of the device;
  • searching for all means to achieve a particular result; and
  • searching for the problem to be solved.

Are there date limits for the search? What are they? How important are these time limits?

  • What time period must I cover? Must I go back to the limit of search material or can I limit the search by time?;
  • often national phase searching will require a date limit to exclude recent results that are past the priority/filing/publication date of the application;
  • is the technology something that has been around for some time? If so, you might find an abstract database doesn’t provides the date range you need – Searching using full text or classification may be more useful; and
  • in certain situations, an application under examination may claim priority from a published document, such as a PCT application. That PCT application may in turn have its own priority document, which may have been filed more than 12 months before the filing date of the application being examined. Where these circumstances arise, examiners should check the priority date of the claims (see 6.1.14 Priority Document).

Has an applicant/inventor search been considered?

In many cases, an applicant/inventor name search will be required. It is the responsibility of the three person team to determine whether (for the search strategy under development) one of the identified exceptions applies (see 4.3.6 Applicant/Inventor Name Searching).

Has the 3PT agreed on the final search strategy?

Strategy should be checked for errors in spelling, truncation, syntax etc.

Amended Reasons

Amended Reason Date Amended
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