The International Genealogical Index or IGI has been a family history source since it was first published in 1973 as the Computer File Index. Additions were made to the IGI until 2008. The Index contains hundreds of millions of records. The IGI is online on the FamilySearch.org website under the Search tab link:
The pull-down menu shows a link to "Genealogies" which will show the page you see at the beginning of this post. The blue menu at the bottom of the image gives you the option of searching all four databases or focusing in on the IGI.
As pointed out by the FamilySearch.org Research Wiki article on the IGI, the database has some basic limitations:
Information in the IGI came from two sources:
1. Some of the entries in the IGI were indexed by the genealogical community from collections of vital and church records (approx. 460 million names). Indexed records are valuable sources of primary information. Unfortunately, attempts to prevent duplication resulted in the exclusion of some indexed records.
2. Some of the information in the IGI was contributed by members of the Church about their ancestors (approx. 430 million names). The quality of this information varies. Duplicate entries and inconsistent information are common. Always verify contributed entries against sources of primary information.There are a number of further limitations in the IGI:
The International Genealogical Index is a finding aid. Always check original sources. Entries often do not contain all the information in the original records, such as death dates or names of additional relatives. Sometimes only portions of parish records or other sources were indexed.
Today’s implementation of the International Genealogical Index addresses key deficiencies in the previous implementation. However, it is not able to correct all of them.
1. Previously, the IGI could not be searched by city or parish name, but only by country and one subdivision (such as U.S. state or U.K. county). Users compensated by searching by batch number. While batch number searching is still supported, most users will prefer searching by name instead of number.
2. Previously, indexed entries and community contributed entries were mixed into a single collection. The reliability of the two is different, so users needed to know the source of each result. Users compensated by examining the first digit of the batch number of each result. Batch number charts assisted users in recognizing indexed (“extracted”) entries and user contributed entries. Today, the two types are searched separately, assisting users to distinguish between them.
3. While it grew to contain a tremendous amount of duplication, the IGI was originally envisioned as a file containing just one entry for each birth and each marriage that has ever occurred. When new records were indexed, entries were discarded that duplicated existing IGI entries. To compensate for this limitation, when an entry is not found among indexed entries, search the community contributed entries as well.
4. The original sources for entries in the IGI are not shown. For an indexed entry, look up the film number in the FamilySearch or FamilySearch Catalog. For a community contributed entry, the contributor may or may not have specified a source. See “Finding the Source of IGI Batch Numbers” for more information.The IGI also exists as a standalone database in the FamilySearch.org Historical Record Collections.
As this page points out, there are two separate "parts" of the IGI:
The International Genealogical Index was a family history database that listed several hundred million names of deceased persons from throughout the world. Names in the IGI came from two sources.
Community Contributed IGI (Personal family information submitted to the LDS Church)
For a short period of time duplication in the IGI was reduced by removing records from the indexed data when these records were submitted by the community. To do an exhaustive search for your ancestor you should choose to search the Community Contributed IGI and follow the process outlined on the Family Search Wiki IGI page to determine if the record you find was part of an indexed collection.
Community Indexed IGI (Vital and church records from the early 1500s to 1885)
The indexed data has been organized into the original collections from which it was transcribed and resides in the Historical Records system. To see a list of all collections available choose Browse All Published Collections from the home screen. The Community Indexed search from this page searches ONLY the records that were part of the old IGI. Most of these collections have had many more records added to them. To do an exhaustive search for your ancestors you should choose to use the search form on the home screen.The history of the information that went into the IGI is actually more complicated than this short explanation. This explanation properly sends you back to the Research Wiki article cited above.
Here are some more links with additional information from the Research Wiki:
- Finding the Source of IGI Batch Numbers
- Ordinance Index (1840-1997) (in the "LDS Temple Records" section of Tracing LDS Families
- Finding Unrestricted Film Numbers for Selected Restricted IGI Films
- How Can I Find the Name of the Submitter in the IGI?
- IGI Batch Number Descriptions
- IGI Batch Numbers for the British Isles and North America
- IGI Batch Numbers for Latin American Countries
- Wales and the IGI
- Global Batch Numbers for the International Genealogical Index (link library for IGI batch sites for Argentina, Belgium, Canada, Channel Islands, Chile, Denmark, England, France, Germany, India, Ireland, Italy, Mexico, The Netherlands, Norway, Peru, Scotland, Spain, Sweden, USA, Uruguay, and Wales)
- Find ancestors on the IGI (Step 8. in Pacific Island Guide to Family History Research)