topic Re: linking levels in Discrete Choice experiment in Statistical Procedures

linking levels in Discrete Choice experiment

oraider — Mon, 21 Jun 2010 21:08:42 GMT

Dear all,

I am going to conduct a discrete choice experiment about tariff choice.
In the experiment, i want to include a discount for contract duration, that is, the longer the contract the higher the discount on final price.

Thus, i have the attribute CONTRACT with levels 0, 12 and 24, and i have the attribute PRICE I with levels of +5, 0 and -5.

I now want to link the levels of the first attribute to the ones of the second, so that every time an alternative possesses the CONTRACT level 24, the PRICE I level is -5, for instance.

I hope someone can tell me how i can program this, and if it is doable at all.

Thanks a lot!

Re: linking levels in Discrete Choice experiment

Ksharp — Tue, 22 Jun 2010 07:56:56 GMT

Hi. I do not understand your purpose total.
Plz, give an example and what target do you need to achieve.

Re: linking levels in Discrete Choice experiment

oraider — Tue, 22 Jun 2010 11:34:17 GMT

Okay, let me explain it to you in more detail.

I have a discrete choice / choice-based conjoint experiment with the 4 attributes:
- QoS
- speed
- contract duration (0 / 12 / 24)
- max. usage in giga byte (7.5 / 10 / 12.5)

Another attribute is supposed to be
- price

However, using this setting, awkward combinations would come up. Thus, I was planning to delete the initial price attribute and replace it by two other price attributes:
- price I (price per giga byte)
- price II (discount for longer contract duration)

Price I:
- 1 level: $3.99
- is to be multiplied with a corresponding "max usage in gb" level (e.g. "10")

Price II:
- 2 levels: "$5" and "$0"
- "$5" is only allowed to show up in combination with the level "0" of the "contract duration" attribute
- "$0" is only allowed to show up in combination with the levels "12" and "24" of the "contract duration" attribute
- is to be added to the result of the Price I multiplikation above.

Here is one example:

Alternative 1
QoS "good"
Speed "very fast"
Contract "0 months"
max. usage "10 gb"
price I "$39.90" (as 10x$3.99)
price II "5$"

Alternative 2
QoS "excellent"
Speed "normal"
contract "12 months"
max. usage "12.5 gb"
price I "$49.90" (as 12.5x$3.99)
price II "$0"

Attributes price I & II are for the design only. In the questionnaire, the respondent will see one uniform price attribute only.

What I need to know is, how do I assign the levels of "price II" to the corresponding levels of "contract duration", as "$5" is not supposed to be combined with "12" and "24", but only with "0".

I hope this made my problem more clear. Many thanks in advance!

Re: linking levels in Discrete Choice experiment

Ksharp — Fri, 25 Jun 2010 04:19:34 GMT

Sorry. Respond it so late.
But not see what your data look like and what your output look like.
Is your contract duration numeric variable?
It seems to be a format problem.
But I am not sure whether the following is what you need.

[pre]
proc format;
invalue pricefmt
0 = 5
12,24= 0;
run;

..................
price_two = input(contract_duration_value,pricfmt.);
format price_two dollar4.;

[/pre]

Ksharp