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Impacts of Food Hypersensitivities on Quality of Life in the UK and Willingness to Pay (WTP) to remove those impacts

Appendix P. Contingent Valuation Results: Adults

After respondents had completed the Discrete Choice Experiment, they were asked two open ended Contingent Valuation Method (CVM) questions.

Last updated: 15 December 2022
Last updated: 15 December 2022

First, they were asked what is the most they would be willing and able to pay to remove their FHS for a temporary period. They were randomly assigned a duration of 1 year, 3 years or 5 years. 

They were then asked what is the most they would be willing and able to pay to remove their condition permanently.

Adult CVM Results: Temporary Removal

CVM Results: Temporary Removal in Aggregate

The mean WTP values for 1 year, 3 years or 5 years of removal for the pooled data are £696, £1678 and £2174 respectively, the median values are £100, £300 and £500 respectively – these median values correspond to a WTP value of £100/year.

Table 1. Summary statistics: Whole Sample by Removal Period

Removal period mean sd N min p25 Median p75 Max
1 year 696.13 2559.23 424 0 0 100 500 40000
3 year 1678.01

6230.84

423 0 5 300 1200 100000
5 year 2173.51 4585.68 418 0 10 500 2500 50000

CVM Results: Temporary Removal by Condition

The mean WTP values for 1 year, 3 years or 5 years of removal for adults with a food allergy are £716, £1681, £2135 respectively, the median values are £100, £300 and £500 respectively – these median values correspond to a WTP value of £100/year.

Table 2. Summary statistics: Food Allergy by Removal Period 

 

Removal period mean sd N min p25 Median p75 Max
1 year 716.16 1869 117 0 0 100 500 15000
3 year 1680.85

4266.34

109 0 1 300 1000 30000
5 year 2135.45 4248.54 97 0 15 500 2500 30000

The mean WTP values for 1 year, 3 years or 5 years of removal for adults with coeliac disease are £682, £1713 and £2011 respectively, the median values are £100, £300 and £875 respectively.

Table 3. Summary statistics:  Coeliac Disease by Removal Period 

 

Removal period mean sd N min p25 Median p75 Max
1 year 682.03 1919.42 179 0 0 100 500 15000
3 year 1712.81

4814.34

183 0 0 300 1500 50000
5 year 2011.41 3435.62 192 0 0 875 2500 25000

The mean WTP values for 1 year, 3 years or 5 years of removal for adults with a food intolerance are £698, £1627 and £2443, the median values are £100, £250 and £500 respectively.

Table 4.  Summary statistics:  Food Intolerance by Removal Period 

Removal period mean sd N min p25 Median p75 Max
1 year 697.53 3668.8 128 0 .5 100 250 40000
3 year 1627.04 8857.31 131 0 50 250 1000 100000
5 year 2443.41 6102.64 129 0 30 500 2000 50000

The relationship between the mean WTP and the removal period is monotonic, with evidence of declining value of additional years (annual value is lower for 3 or 5 years of removal, than for 1 year). 

Table 5.  CVM WTP Values, in aggregate and by Condition
 

Value years Mean, £ /year years Median, £ /year
Aggregate 1 696 696 1 100 100
Aggregate 3 1678 559 3 300 100
Aggregate 5 2174 435 5 500 100
Allergy 1 716 716 1 100 100
Allergy 3 1681 560 3 300 100
Allergy 5 2135 427 5 500 100
Coeliac 1 682 682 1 100 100
Coeliac 3 1713 571 3 300 100
Coeliac 5 2011 402 5 875 175
Intolerance 1 698 698 1 100 100
Intolerance 3 1627 542 3 250 83
Intolerance 5 2443 489 5 500 100

Figure 1 Distribution of open ended WTP by period: adults

Tables explain the data in full. Tables explain the data in full. Tables explain the data in full.

CVM Results: Permanent Removal

The mean WTP value for permanent removal for the pooled data was £5367, the median value was £1000.

Table 6.  What is the most you are willing to pay for permanent removal of your condition?

- mean std. Dev N Min p25 Median p75 max
Maximum WTP 5366.8 11203.133 299 0 300 1000 5000 100000

The mean WTP value for permanent removal of food allergy, coeliac disease and food intolerance conditions are £6184, £6996 and £4054 respectively.

Table 7.  What is the most you are willing to pay for permanent removal of your condition? By Only or Worst Condition

Only or worst condition mean sd N min p25 Median p75 max
Food allergy 6183.7 13166.96 366 0 70 5000 5000 100000
Coeliac disease 6996.3 14326.14 584 0 500 2500 7000 100000
Food intolerance 4054.3 9796.37 419 0 100 1000 5000 100000