# Combining Value Sets

Combining Value Sets work similarly to the Combining reference sets feature. Combining Value Sets enables users to create a new Value Set by merging two existing ones. Combining Value Sets can be performed either by invoking the

`Tools > Combine Value Sets…`

menu or by right-clicking on a Value Set and selecting **Combine…**Value Sets view context menu - Combine...

Tools | Combine Value Sets...

The following methods are available to combine two Value Sets named A and B:

Method | Math Formula | Description |

Union | `A U B` | The resultant set contains all the elements in either A or B or both |

Intersection | `A Ո B` | The resultant set contains the elements present in both A and B |

Complement | `A-B - A\B` | The resultant set contains everything in A but not present in B |

Complement | `B-A - B\A` | The resultant set contains everything in B but not present in A |

Symmetric
difference | `(A\B) U (B\A)` | The resultant set is the intersection subtracted from the union |

Combine Value Sets - Select method

After selecting one of them, click the

**Next**

button. To complete the operation, the Preferred Term and source for the new combined Value Set needs to be set on the last wizard page.Combine Value Sets - Properties

Hit the

**Finish**

button and the new Value Set is created. Its editor opens automatically.Last modified 6mo ago