Table 1

A priori groups of variables used in analyses

Variable groupPotential risk factorsData source
Model 1: Maternal demographic factorsEthnicity, whether born in the UK, education level,* maternal age,* parental employment,* financial security, size of householdBiBBS baseline questionnaire
Model 2: Maternal language factorsNative language, languages spoken at homeBiBBS baseline questionnaire
Model 3: Perinatal factorsBirth weight, preterm statusLinked health data (maternity records)
Model 4: Distal child factorsChild sex, child ageLinked health data (maternity records), Talking Together service data
Model 5: Proximal child factorsReceptive vocabulary score, parent-reported hearing concernsTalking Together service data (Oxford CDI-Short; parent-reported questionnaire)
  • For information on how data was linked, see online supplemental supporting information.

  • *This variable was derived using the data source listed. See online supplemental supporting information for further details.

  • BiBBS, Born in Bradford’s Better Start; CDI, Communicative Development Inventory.