To be determined
To Be Announced (TBA), To Be Confirmed (TBC), and To Be Determined (TBD), almost always used in their abbreviated forms, denote that the datum of which TB(A/C/D) is a stand-in is yet to be announced/confirmed/determined at the time of writing.
The acronyms are often applied in early-to-mid-stage engineering project documentation and preliminary contracts in industry. Although used for all kinds of interim/preliminary or unknown-at-the-time-of-writing data, the most common uses in engineering documents and contracts are related to:
- dates of commencement, completion, etc; estimated total or remaining time to do a specific work task
- money amounts, i.e. costs, prices
- physical or derived quantities as-yet-to-be-obtained from tests/measurements
- engineering values depending on one or more of the above, with safety margins included