sampling, they are then given a list of positive and negative feelings and are asked to evaluate
how strongly they felt each of these emotions during this particular episode. The advantages
of DRM over ESM are that it imposes a considerably smaller burden on respondents, does not
disrupt normal activities, assesses all episodes over the entire day and not just particular
moments, and provides time-budget information. Kahneman et al. (2004a) also show that
DRM and ESM lead to similar results. Hence, DRM provides an efficient approximation to
the results of the ESM (Kahneman and Krueger 2006).
One way to conduct comparisons of the experienced utility between different individuals
is to aggregate the respondents’ assessments of the various emotions into a unique index
number. For each activity, respondents evaluate a range of feelings, which are either positive
(e.g., “happy”, “enjoy myself”, “friendly”) or negative (e.g., “depressed”, “angry”,
“frustrated”), on a scale from, for example, 0 to 10. One common measure of mood that
aggregates these answers is net affect. Net affect A is defined as the difference between the
average score the respondent gives to all positive attributes and the average score of all
negative attributes. Defining Ajj as person i’s net affect during activity j, we have
LK
Aij
∑PAilj ∑NAikj
(1)
l=1 k=1
L K
where PAjj represents the affect score of the l-th (out of L) positive emotion person i reports
for activity j, and NAjk represents the affect score of the k-th (out of K) negative emotion.
Kahneman et al. (2004b) propose calculating a person’s experienced utility as the integral of
the stream of pleasures and pains associated with events over time so that
Ai= ∑hijAij, (2)
j
where hij is the fraction of total waking time person i spends on activity j. To aggregate
emotional affects according to , one has to assume that net affect is a cardinal measure, that
utility is time-separable, and that the measure of net affect is a meaningful representation of
the utility derived from an experience. Kahneman et al. (2004b) provide evidence of the
correlation between net affect and objective circumstances that suggests that the use and
interpersonal comparisons of affect measures are meaningful and add useful information to
our understanding of well-being.