GM_ICW Table

The GM_ICW table records GEDmatch in-common-with (ICW) relationships — pairs of kits that both match each other. Each row links two kits and records how much DNA they share. This is the data behind clustering: knowing which of your matches also match one another.

GEDmatch gathering is currently unavailable in the Client and is expected to return in a future update. This page documents the schema and the behavior of the existing gather code as written.

kita and kitb

kita and kitb are the two kits in the in-common-with relationship. As elsewhere in the GEDmatch tables, kita is treated as the primary side and kitb as the other kit. ICW rows are written bidirectionally — each relationship is inserted twice, once as (kita, kitb) and once with the two swapped — so the relationship can be queried from either kit’s perspective.

No explicit primary key. Unlike the other GEDmatch tables, GM_ICW has no Id / primary-key column. Rows are de-duplicated at insert time (insert-or-ignore on the kit pair) rather than keyed by a surrogate id.

How It Is Populated

ICW rows come from the ICW / triangulation stage of a GEDmatch gather and from AutoSegment link data (the “links” between nodes in a cluster graph). The cM value is read from whichever shared-cM field the GEDmatch response provides (total_cm, totalCM, shared_cm, or cM); AutoSegment links are stored without a cM value.

Column Reference

Column	Type	Description
kita	string	The primary kit in the in-common-with pair. References `GM_Kit.kit_num`.
kitb	string	The other kit in the pair. References `GM_Kit.kit_num`.
totalCM	float	Total shared DNA between the two kits, in centimorgans. 0 when the source (e.g., AutoSegment links) does not provide a value.

Related Tables

GM_Match — the match summary; its icwdate is set when ICW data is gathered for a pair.
GM_Kit — resolves kita / kitb to people.
GM_TriangulatedSegment — triangulated clusters built from overlapping shared segments.