This document summarizes a study exploring how currently experiencing a health state may affect how that health state is valued. The study compares ratings from an "experience-based" group who are currently in a given health state to a "non-experience-based" group who are not currently in that state. Preliminary results show some health states are rated slightly higher when experienced, though differences are small and not seen for all states. Larger datasets will be needed to further analyze how experience may influence health state valuations.

1. Do you know what you are talking about?
Differences in the TTO valuation of (currently) experienced
and non-experienced health profiles
Cubi-Molla, Patricia1; Devlin, Nancy1; Shah, Koonal1; Herdman, Mike1
Contact: Patricia Cubi-Molla • Email: pcubi-molla@ohe.org • Tel: +44 (0)20 7747 8868 • Mobile: 07766912502
BACKGROUND
Literature supports the idea that health states are usually
evaluated more positively when they are experienced than
when they are imagined (De Wit et al., 2000). This
discrepancy is the basis of the debate about using public- or
patient-based preferences. The choice of the former or the
latter may lead to significantly different value sets, and it is
not clear whether it is desirable for health state values to be
influenced by the prior experiences of respondents
Acknowledgements
The authors want to thank Dr. Elly A. Stolk for her
feedback on a preliminary version of the project
References
De Wit, G. A., Busschbach, J. J. & De Charro, F. T., 2000. Sensitivity and perspective in the valuation of
health status: whose values count?. Health Economics, 9(2), pp. 109-126
Dolan, P., 1997. Modeling Valuations for EuroQol Health States. Medical Care, Volume 35, pp. 1095-1108
METHODS
Nancy will be in the “experience-based” (EB) group associated
to a health state H if she reported H as her own health state in
[1], and H is one of the profiles she valued via TTO and VAS in [2]
Koonal will be in the “non-experience-based” (NEB) group
associated to H if H is one of the profiles he valued via TTO and
VAS in [2], but he did not report H as his own health state in [1]
Methods:
(1) Probit regression models controlling for X = (sex, age, age
square, if parents, if employed, and several social group and
education), to analyse the characteristics of the EB group
(2) ANOVA and Mean comparison (t-tests) of TTO, VAS and VAS
adjusted values by group, to look for significant differences
in the values between EB and NEB groups
(3) Different OLS regression models to establish the effect of
currently experiencing the health profile to be valued on the
observed TTO value, controlling for X
(4) Pearson’s or Fischer’s tests to explore differences in the
ranking position of each profile with respect to death, for EB
and NEB groups
(5) Replicate the Dolan N3 model for generating the tariffs, but
adding being in the EB group as an explanatory factor.
(6) Compare EQ-VAS from "own health state" vs. raw VAS value
from "hypothetical health state" (test if difference = 0)
RESULTS
DISCUSSION / CONCLUSION
• In general, EB values for TTO and VAS seem to be slightly higher
than the NEB values. However this is not observed for all the
selected profiles. It is also not clear if VAS and TTO follow the
same pattern, that is, if being currently experiencing a health
state affects similarly the VAS and TTO valuation of it
• We cannot find evidence supporting the application of different
weights to the EQ-5D dimensions for creating the TTO values.
• Caveat: small subsamples!
• Work in progress: larger datasets (pooled across countries?)
could be used to check if the results are robust to alternative
definitions of the NEB group; extend the analysis to alternative
definitions of “experience”.
• From (1) we can suggest that the differences (if any) between
the values assigned by the EB and NEB can only be attributed to
the fact that the rater is currently living in the same health state
as the profile she is valuing (e.g. rather than to observable
characteristics of the sample)
DEFINING “EXPERIENCE”
Imagine we ask Nancy to value a health state H. The idea that
Nancy has “experience in H” has several interpretations:
i. Personal experience (“feeling”)
a. Nancy is currently living in H
b. Nancy lived in the past in H
ii. Vicarious experience (“knowledge”)
a. Affective: Nancy knows someone very closely attached to her
who lived/lives in H (e.g. relative, informal carer)
b. Non-affective: Nancy knows someone distant to her who
lived/lives in H (e.g. health professionals, formal carers)
1 Office of Health Economics, London
What we
study here
DATA MVH Study database (Dolan, 1997) n= 2,958
Every respondent:
[1] described their own health state using the EQ-5D-3L descriptive
system and EQ-VAS score
[2] ranked 12 EQ-5D-3L hypothetical profiles, together with “11111”,
“Unconscious” and “Immediate death”, and valued them by using:
- EQ-VAS (Raw or later on Adjusted by anchoring them between
“11111” and “Death”)
- TTO protocol (Adjusted to [-1,1], with death = 0)
AIM
Explore how currently experiencing a health state H may
affect the TTO or VAS valuation of H
EB group NEB group Total
Profile n % % Cum. n n
21111 57 22.89 22.89 1,103 1,160
11112 51 20.48 43.37 1,138 1,189
11121 51 20.48 63.85 1,132 1,183
11211 22 8.84 72.69 1,177 1,199
11122 19 7.63 80.32 711 730
12111 18 7.23 87.55 1,167 1,185
21222 14 5.62 93.17 713 727
22222 7 2.81 95.98 751 758
Other 10 4.02 100.00 27,355 27,365
Total 249 100 35,247 35,496
Other profiles (frequency): 11131 (2), 22112 (2), 33212 (2),
12211 (1), 21232 (1), 22233 (1), 32211 (1)
Experience- and non-experience- based groups
(1) None of the demographic and socio-economic characteristics in X has been found to be
significant (at 5% level) to explain the group composition. Therefore we conclude that the EB
group associated to a particular EQ profile has randomly selected among those facing the
task of valuing that profile following the TTO protocol
(2) Cells show the differences in means by group
(mean value for experience-based minus mean
value for non-experience-based). Blank cell = no
evidence to reject equal means
range [-1,1] [0,100] [-31.3,1] [0,100] [0,100]
profile TTO VAS VAS_adj Death Full Health
21111 + 0.33*
11112 + 0.04* + 2.91*
11121 + 0.10*** + 4.17** + 0.05***
11211
11122 + 6.00** + 0.08** - 1.24*
12111 + 0.93***
21222 + 8.70** + 0.16*** - 4.71*** + 0.72***
22222 + 0.38*** + 0.08* - 7.26*** n/a
(3) Only significant coefficients for the dummy
being in EB group or not for TTO and VAS
adjusted are shown. Age and age squared are
also found to be significant in most of the
regressions (this is not observed in other
variables in X). Additional OLS regressions have
been run interacting being in EB group or not
with dummies for three age categories, but the
results have not changed significantly
profile TTO [95% Conf. Int] VAS adjust [95% Conf. Int]
21111 -0.059** -0.117 -0.002 -0.066* -0.145 0.012
11121 0.087** 0.011 0.163 0.062* -0.010 0.133
22222 0.352** 0.008 0.695
(4) Differences are not found to be significant for
the position of the selected profiles with respect
to death, either for VAS or for TTO
(5) The Dolan N3 regression model has been applied.
The coefficient is found to be negative (-0.012) but
not significant (z=-0.49). Its inclusion or running
separate regressions for EB and NEB groups hardly
affect the coefficients of the remaining variables
(6) No evidence
that both scores
are significantly
different or one
greater than the
other along all
the profiles
11112
11112
22222
11122
21111
21222
11112
21111
11121
1121111121
1121112111
11122
21222
22222
21111
21111
22222
21222
21222
11211
21111
22222
11112
11122
22222
11122
21111
21111
11122
11121
21111
22222
21222
12111
12111
11121
21222
21111
11112
2111121111
21111
21222
21111
11121
21222
11122
11121
11121
21111
21111
11122
11122
21111
11121
21111
21111
11112
11112
21222
11122
21111
11211
21222
21111
12111
11112
11112
1121121222
12111
21111
22222
11211
11112
12111
11122
11121
11211
11122
21111
11211
11122
11112
11112
21111
2111111122
11121
11211
21111
11121
11211
11112
11121
21111
11121
12111
11121
11121
1121111112
11112
11112
11121
11112
11121
1112111112
11112
11112
1211111211
11121
21111
11121
11211
12111
21111
21222
11121
11112
12111
21222
11112
21111
21111
11121
11121
21111
11112
11122
11112
11121
11112
11112
21111
21111
2111111112
1112221111
2111111122
11122
11112
11112
1111211112
21111
11121
12111
11112
12111
11112
11211
11122
11121
11112
11121
11112
21111
21111
21222
11112
12111
11121
11112
1112112111
21111
11121
11112
11211
11112
11112
2111121111
11112
2111111121
11112
2111111121
12111
11112
11112
11121
21111
11211
1112121111
11211
12111
12111
21111
11121
1112111112
11121
21111
11121
21111
21111
21111
11121
21111
11112
12111
21111
11112
11121
11121
11211
21111
11112
11121
11121
11112
11121
11121
11121
11211
21111
11211
11112
11121
11211
11121
11121
11121
11112
11122
11121
0
.2.4.6.8
1
VASforself-reportedhealthprofile
0 .2 .4 .6 .8 1
VAS for hypothetical health profile
Adjusted VAS values by individual in EB group
22222
21222
11122
21111
11211
12111
11112
11121
0
.2.4.6.8
1
VASforself-reportedhealthprofile
0 .2 .4 .6 .8 1
VAS for hypothetical health profile
Average adjusted VAS by selected EQ profiles - EB group range [0,100] [-31.3,1]
profile N VAS Corr VAS_adj Corr
ALL 248 0.34 0.55
21111 57 - 5.39** 0.07 - 0.092** 0.74
11112 51 + 4.75** 0.21 + 0.067** 0.35
11121 51 0.13 0.01
11211 22 0.34 0.11
11122 19 + 6.00** 0.14 0.34
12111 18 - 5.06* -0.05 - 0.056* 0.07
21222 14 + 8.70** 0.21 0.19
22222 7 0.18 0.28