Anticipated and adjusted expiration dates are value-added dates calculated by IFI to provide the best possible estimate of when a patent is expected to expire.

Anticipated Expiration is based on the simple patent term formula. For recent US grants, this is 20 years from the earliest filing date. The full set of rules (for the US) is here: 

1. Design patents (publication kind S, S1) - issue date + 14 years
2. Reissues (publication kind E, E1) - use expiration date of parent (look up parent using related application type reissue)
3. SIR, pre-grant publications (publication kind H, H1, In, An) - no date to calculate
4. Utility patents, if issue date <=19780608 - issue date + 17 years
5. Utility patents, if filing date >= 19950608 - earliest appdate + 20 years
6. Utility patents, if filing date < 19950608 and issue date > 19780608 and issue date + 17 years > earliest appdate + 20 years - issue date + 17 years
7. Utility patents, if filing date < 19950608 and issue date > 19780608 and earliest appdate + 20 years > issue date + 17 years - earliest appdate + 20 years

Different rules are applied in other countries.

Adjusted Expiration is Anticipated Expiration + Term Extension. For example, see the first page of US-8566251-B2:

In the "Notice" section, it says "Subject to any disclaimer, the term of this patent is extended or adjusted under 35 U.S.C. 154(b) by 96 days. This patent is subject to a terminal disclaimer”. 

The ifi-integrated-content section for this record is:

<ifi-integrated-content publication-type="G" accession-number="06146946" document-category="Utility" subject-area="Electrical">
  <ifi-patent-status anticipated-expiration="20310525" terminal-disclaimer="yes" adjusted-expiration="20310829">
    <ifi-patent-status-description country="US">Active</ifi-patent-status-description>
    <ifi-term-extension>96</ifi-term-extension>
  </ifi-patent-status>

The adjusted-expiration has 96 days added on due to the term extension. But note – there is a terminal disclaimer. We do not know what is in that. So, we tell you that there is one – but cannot do any date adjustment. 

Therefore, "adjusted expiration" is just our best estimate of the expiration date. To get an exact date, you need to open up the file wrapper and see what the terminal disclaimers say, and see if any additional adjustments have been made.

Searching with the Anticipated and Adjusted Expiration Date Fields

The anticipated and adjusted expiration date fields can be useful in searching. However, one must be careful.

For example, if one wants to see how many US grants expire in 2020, it is important to note that the ifi_expdyear_adj field is only present in a record if there has been a term adjustment or extension. When there is no adjustment or extension, there is no adjusted expiration date and users must use the anticipated expiration date.

So if you enter the following search using the anticipated expiration year:

pnctry:US AND pnkind:(A OR B1 OR B2) AND ifi_expdyear:2020

this results in 208,915 records. This is NOT the correct result as it excludes grants with term adjustments and extensions that when adjusted, expire in 2020.

If you perform the same search and replace the anticipated expiration year with the adjusted expiration year:

pnctry:US AND pnkind:(A OR B1 OR B2) AND ifi_expdyear_adj:2020

this results in 32,889 records. This is obviously NOT correct and reflects only those records with populated ifi_expdyear_adj fields (about 15% of the records).

To get the correct number, you must combine the anticipated and adjusted expiration date fields using the "OR" operator in a nested search:

pnctry:US AND pnkind:(A OR B1 OR B2) AND ((ifi_expdyear_adj:2020) OR (ifi_expdyear:2020 AND NOT flags:has_ifi_expdyear_adj))

This results in 167,209 records. It is the sum of:

pnctry:US AND pnkind:(A OR B1 OR B2) AND (ifi_expdyear:2020 AND NOT flags:has_ifi_expdyear_adj)

which results in 134,320 records, and

pnctry:US AND pnkind:(A OR B1 OR B2) AND (ifi_expdyear_adj:2020)

which results in 32,889 records.