Table 1.

Summary of outcome measures and exposure-outcome relationships investigated.

Exposure	Outcome	Outcome description	Geography	Covariates added to controlled model
Postcode district relative deprivation, modelled as deciles (D): D1 = least deprived postcode districts.	Percentage of food outlets registered to accept orders online	The number of food outlets registered to accept orders online, expressed as a percentage of the number of food outlets within a postcode district (bounded, 0–100%).	Postcode district	Postcode district rural urban classification
				Postcode district population density: usual residential and usual workday
	Number of food outlets accessible online	The number of food outlets accessible online based on a postcode district being listed in the delivery area of a food outlet registered to accept orders online.	Postcode district	Postcode district rural urban classification
				Number of food outlets in postcode district
				Postcode district population density: usual residential and usual workday
	Number of unique cuisine types accessible online	The number of unique cuisine types accessible online from food outlets registered to accept orders online who included a postcode district in their delivery area.	Postcode district	Postcode district rural urban classification
				Number of food outlets in postcode district
				Postcode district population density: usual residential and usual workday
				Number of food outlets accessible online
	Percentage of neighbourhood food outlets accessible online	The number of food outlets accessible online expressed as a percentage of the number physically accessible within the neighbourhood (unbounded, may exceed 100%).	1600m Euclidean radius ‘neighbourhood’ buffer of postcode district geographic centroid	Postcode district rural urban classification
				Postcode district population density: usual residential and usual workday