Consumers’ preferences for traditional meat products: production system and objective quality cues in Iberian ham

Figures & data

Table 1. Attributes and levels of the choice experiment.

Attribute	Levels
Price	Acorn-fed Iberian ham (aIH) type:	Fodder-fed Iberian ham (fIH) type:
	€13/100g	€4/100g
	€16/100g	€7/100g
	€19/100g	€10/100g
	€22/100g	€13/100g
Iberian breed purity	50% Iberian breed 75% Iberian breed 100% Iberian breed
Purchase format: Slicing type	‘Hand-sliced’ claim No claim
Dehesa origin claim	‘Produced in the Dehesa’ claim No claim
Pictorial representation of Dehesa	No background (no picture) Background-Agricultural system Background-Dehesa system Background-Dehesa system with pigs

Figure 1. Example of choice card.

Table 2. Variables related to the production agrosystem of origin Dehesa.

Variable	Description (units)	Mean	St. Dev.
KNOW	Knowledge about the Dehesa agrosystem: Correct identification of the Dehesa picture (No = 0, Yes = 1)	0.84	–
ENVIV	Use value of environmental services provided by the Dehesa: Hunting and mushroom/berry picking (0 = No, 1 = Yes)	0.22	–
VISIV	Use value of Dehesa landscape: Visit the Dehesa countryside during the last year (No = 0, Yes = 1)	0.27	–
CULTV	Acknowledging cultural values attached to the Dehesa: Agreement with ‘There are important traditions, folklore, and crafts associated with the Dehesa’ (Likert 1-7)	5.51	1.29
TASTEYES	Agreement with ‘Food products coming from the Dehesa taste better’ (No = 0, Yes = 1)	0.80	–
PROPROV	Place of residence-province: Geographical location in province where acorn-fed Iberian ham is produced (No = 0, Yes = 1)	0.43	–
RURPRO	Place of residence-municipality: Geographical location in rural municipality in province where acorn-fed Iberian ham is produced (No = 0, Yes = 1)	0.19	–

Table 3. Random parameter logit model (RPLM).

	Mean		SD
	Coef.	SE	Coef.	SE
Parameter mean values
Acorn-fed (aIH)
Breed purity-75% Iberian	0.321**	0.162	1.250***	0.425
Breed purity-100% Iberian	0.347**	0.158	1.003***	0.360
Hand-sliced claim	-0.109	0.331	2.592***	0.219
Produced in the Dehesa claim	0.323**	0.136	0.006	0.320
Background-Agricultural system	1.607***	0.594	1.016***	0.350
Background-Dehesa system	-0.216	0.263	0.706***	0.235
Background-Dehesa system with pigs	0.093	0.186	0.257	0.260
Price	-0.273***	0.020	0.145***	0.014
ASCa	3.190***	0.442	3.609***	0.221
Fodder-fed (fIH)
Breed purity-75% Iberian	0.277*	0.154	0.601**	0.279
Breed purity-100% Iberian	0.592***	0.152	0.923***	0.306
Hand-sliced claim	0.584***	0.137	1.918***	0.192
Produced in the Dehesa claim	-0.038	0.105	0.235	0.255
Background-Agricultural system	1.151*	0.592	1.228***	0.311
Background-Dehesa system	0.038	0.102	0.959***	0.283
Background-Dehesa system with pigs	0.334*	0.199	0.444	0.272
Price	-0.097***	0.021	0.233***	0.026
ASCf	0.771**	0.363	3.269***	0.211
Heterogeneity in the mean
ASCa × VISIV	0.674*	0.356
ASCf × VISIV	−0.544*	0.302
ASCa × TASTEYES	2.418***	0.379
ASCf × TASTEYES	0.764**	0.341
Hand-sliced claim (acorn-fed)×KNOW	0.859**	0.358
Background-Agricultural system (acorn-fed)×CULTV	−0.192*	0.100
Background-Agricultural system (fodder-fed)×CULTV	−0.191*	0.102
Background-Dehesa system (acorn-fed)×ENVIV	1.056***	0.379
Background-Dehesa system (fodder-fed)×ENVIV	0.785**	0.341
Background-Dehesa system (fodder-fed)×RURPRO	−0.827**	0.370
Background-Dehesa with pigs (fodder-fed)×PROPROV	−0.526**	0.239
Model fit statistics
LL	−5123.62
Pseudo-R^2		0.329
AIC/N		1.488
Observations (individuals)	6948 (1158)

***; **; * denote significance at 1%, 5%, and 10% level, respectively.

Table 4. Marginal willingness to pay (WTP) by attribute (in €/100 g-package of Iberian ham).

Type	Characteristic	Mean	Confidence interval (95%)
Acorn-fed (aIH)	Breed purity-75% Iberian	1.18**	(0.01 - 2.35)
	Breed purity-100% Iberian	1.27**	(0.12 - 2.42)
	Hand-sliced claim	2.63**	(0.45 - 4.82)
	Produced in the Dehesa claim	1.19**	(0.20 - 2.17)
	Background-Agricultural system	2.01***	(0.70 - 3.33)
	Background-Dehesa system	0.84***	(0.24 - 1.44)
	Background-Dehesa system with pigs	0.34	(-0.97 - 1.66)
	Type of IH: Acorn-fed (ASCa)	19.49***	(17.76 - 21.21)
Fodder-fed (fIH)	Breed purity-75% Iberian	2.86	(-0.63 - 6.35)
	Breed purity-100% Iberian	6.11***	(1.65 - 10.57)
	Hand-sliced claim	6.02**	(1.42 - 10.62)
	Produced in the Dehesa claim	−0.39	(-2.73 - 1.95)
	Background-Agricultural system	1.04	(-3.13 - 5.21)
	Background-Dehesa system	0.14	(-1.80 - 2.08)
	Background-Dehesa system with pigs	1.13	(-2.51 - 4.78)
	Type of IH: Fodder-fed (ASCf)	12.73***	(7.35 - 18.11)

*** and ** denote significance at 1% and 5% level, respectively. Estimates obtained using the Krinsky and Robb (1986) method (5000 replications).

Table 5. Total willingness to pay (WTP) for different Iberian ham products (in €/100 g-package of Iberian ham).

Product	Mean profile		Profile Aware of Dehesa values: user, cultural identity		Profile Unaware of Dehesa values: non-user, no cultural identity
	Mean	Conf. int. (95%)	Mean	Conf. int. (95%)	Mean	Conf. int. (95%)
I. Acorn-fed, Breed purity-100%, No Hand-sliced claim, No Produced in Dehesa claim, No background	20.76	(18.75–22.77)	22.55	(19.81–25.30)	20.08	(17.94–22.22)
II. Acorn-fed, Breed purity-100%, Hand-sliced claim, No Produced in Dehesa claim, No background	23.39	(20.36–26.43)	25.19	(21.69–28.69)	22.71	(19.55–25.88)
III. Acorn-fed, Breed purity-100%, Hand-sliced claim, Produced in Dehesa claim, No background	24.58	(21.54–27.61)	26.37	(22.79–29.95)	23.90	(20.73–27.07)
IV. Acorn-fed, Breed purity-100%, Hand-sliced claim, Produced in Dehesa claim, Background-Agricultural system	26.59	(23.63–29.56)	27.34	(23.73–30.96)	27.69	(23.92–31.45)
V. Acorn-fed, Breed purity-100%, Hand-sliced claim, Produced in Dehesa claim, Background-Dehesa system	25.42	(22.28–28.56)	30.25	(25.55–34.95)	23.90	(20.73–27.07)
VI. Fodder-fed, Breed purity-50%, No hand-sliced claim, No Produced in Dehesa claim, No background	12.73	(7.35–18.11)	8.65	(2.15–15.15)	14.27	(8.03–20.50)
VII. Fodder-fed, Breed purity-50%, Hand-sliced claim, No Produced in Dehesa claim, No background	18.75	(10.55–26.95)	14.67	(6.80–22.54)	20.29	(11.36–29.22)
VIII. Fodder-fed, Breed purity-50%, Hand-sliced claim, Produced in Dehesa claim, Background-Agricultural system	19.78	(11.08–28.49)	12.79	(4.61–20.96)	26.27	(13.26–39.27)
IX. Fodder-fed, Breed purity-50%, Hand-sliced claim, Produced in Dehesa claim, Background-Dehesa system	18.89	(10.42–27.36)	13.05	(5.50–20.60)	18.67	(10.26–27.07)
X. Fodder-fed, Breed purity-100%, No Hand-sliced claim, No Produced in Dehesa claim, No background	18.84	(8.79–28.89)	14.76	(7.31–22.21)	20.38	(11.94–28.81)

All the estimates of total WTP are significant at 0.1%, except VI and VIII, which are significant at 1% for ‘Profile Aware’. Estimates obtained using the Krinsky and Robb (1986) method (5000 random draws). Non-user/User indicates ENVIV = 0/1 and VISIV = 0/1 and No cultural identity/Cultural identity indicates CULTV = 3/7. Regarding the latter, respondents answering 1, 2 and 3 were considered not to believe that Dehesa is significantly associated with cultural heritage.

Figure A1. Categories of Iberian ham according to the Quality Standard regulation (BOE 2014). ¹Source: Adapted from Spain Food Sherpas (2018) and ASICI (2020). The grey dotted lines show product alternatives that may be technically possible but are not market-oriented since there is no incentive for investing in breed purity when the end product would have lower meat yield (the Iberian breed is smaller) and the lowest quality (and, accordingly, the lowest price). In addition, it is worth noting that from a market perspective there is no clear incentive for having high-breed-purity Iberian pigs (100% or 75%) if they are not going to be used to produce the highest quality (black or red label).

Table B1. Descriptive statistics of the socio-demographic variables of the sample.

Description (units)	Mean	St. Dev.
Sex: Male [%]	53.4%	–
No. people in the household	2.84	1.31
No. of children under 18 in the household	0.68	0.99
Age	51.58	15.74
Educational level: No studies [%]	5.4%	–
Educational level: Primary studies [%]	32.6%	–
Educational level: Secondary studies [%]	40.2%	–
Educational level: University studies [%]	21.9%	–
Total household income less than €1,000 / month [%]	11.0%	–
Total household income between €1,000 and €2,000 / month [%]	44.7%	–
Total household income between €2,000 and €3,000 / month [%]	31.4%	–
Total household income between €3,000 and €4,000 / month [%]	11.4%	–
Total household income between €4,000 and €5,000 / month [%]	1.3%	–
Total household income more than €5,000 / month [%]	0.2%	–

Krinsky I, Robb AL. 1986. On approximating the statistical properties of elasticities. Rev Econ Stat. 68(4):715–719.

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BOE (Boletín Oficial del Estado). 2014. Real Decreto 4/2014, de 10 de enero, por el que se aprueba la norma de calidad para la carne, el jamón, la paleta y la caña de lomo ibérico. Madrid: Boletín Oficial del Estado.

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Data availability statement

The data that support the findings of this study are available from the corresponding author, R. Granado-Díaz, upon reasonable request.