Choice Based Conjoint (CBC) & estimation for market shares

Hello everyone,

I like to conduct a choice based conjoint analysis (CBC) with a no-
choice option. So far, so good.

The subsequent analysis allow to estimate market shares as we can see
how often a specific configuration was chosen. But those market shares
are of course quite high as participants tend to decide for a
configuration in a simulation more easily than to buy it. On the other
hand, in real life are much more alternatives available than in our
simulation.

Consequently, the idea is to adjust those simulated shares to real,
past market shares or something like that.
Does anyone know a source or got some information about this
procedure?
In the web, I sometimes found some examples as a result, but not the
way to get those results.

I am aware of the fact, that this adjustment is also only a better
estimation and not the truth.

Many thanks in advance,
Tom
.