Skip to main content

Table 2 NHS Digital match algorithm

From: Assessing the impact of specialist home visiting upon maltreatment in England: a feasibility study of data linkage from a public health trial to routine health and social care data

Step (match rate)a NHS number DoB Sex Postcode
1 Exact Exact Exact Exact
2 Exact Exact Exact
3 Exact Partial Exact Exact
4 Exact Partial Exact
5 Exact Exact
6b Exact Exact Exact
7c Exact Exact Exact
8 Exact
  1. aMatching at step 1 or 2 would provide greatest reassurance of valid match
  2. bWhere NHS number does not contradict the match and DOB is not 1 January and the postcode is not in the ‘ignore’ list
  3. cWhere NHS number does not contradict the match and DOB is not 1 January