Genealogical research without a well-documented family group in your hand is like piloting an underwater submarine with no periscope, charts, sonar, radar, radio, GPS, depth gauge, compass, or speedometer. No submarine captain would think of leaving port without these tools for determining his position. Likewise, genealogists should never leave port without their most valuable position finding tool—a well-documented family group record.
The genealogical process involves a lot of guessing (or hypothesis) about names, dates, places, relationships, and sources. We start with guesses about some of these, and then go out to find the sources and evidence that prove or disprove those guesses.
This means that genealogists need to be good guessers. Good guessers use all the clues available to them before making their best guess. The key principle is straightforward:
THE MORE YOU KNOW, THE BETTER YOU CAN GUESS.
The more complete the family group record, the better the genealogist will be at finding the evidence to prove it. The more you know about a person's name and the way he used it, the more likely you are to recognize it, even garbled, in a document. The more you know about where a person resided and made his living, the more likely you are to find documents to prove it. The more you know about the dates of events in a person's life, the more likely you are to find documents to prove it. The more you know about a person's relatives and associates, the more likely you will be able to distinguish him from others with similar names. The more you know about what types of sources contain which information, when those sources were compiled, and where they are stored, the more likely you are to find useful sources.
Genealogy is the art of building what is known or suspected into a more and more complete picture by adding more information piece by piece. As you begin genealogical research on a new person or family, it is important to prepare a well-documented family group record right from the start. The family group serves as a roadmap to further research. It is the most succinct view of the genealogical clues. It shows what you already know or believe about the names, dates, places, relationships, and sources of the information. It is the basis for good guessing and good research. Start with a well-documented family group record.
For further information about how to put together a well-documented family group record, see the following FamilySearch Wiki articles: