Millisecond Forums

hello,

i have a problem with my paired comparison design! according to a few entries to "conjoint analysis", i designed it exactly like it was demonstrated. i wanted to compare 20 different car pics, so there must be 190 comparisons for a complete comparison.  the problem is, that my data tells me, that not every
picture is paired with each other. a few pics are shown 14 times, others 17 and so on. is there any mistake in my programming? the only thing i´ve changed is that instead of trials i use likert to rate the pics in addition.

+++++++++++++++++++++++++++++++++++++++++++++++++++
Counter "Paired Comparison"
+++++++++++++++++++++++++++++++++++++++++++++++++++

<counter pic1selector>
/ items = (
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10,
11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11,
12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12.
13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13,
14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14,
15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16. 16. 16. 16, 16, 16,
17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17,
18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18,
19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19. 19, 19, 19, 19, 19, 19, 19,
20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20)
/ select = noreplace
</counter>

<counter pic2selector>
/ items = (
2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20,
1, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20,
1, 2, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20,
1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20,
1, 2, 3, 4, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20,
1, 2, 3, 4, 5, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20,
1, 2, 3, 4, 5, 6, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20,
1, 2, 3, 4, 5, 6, 7, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20,
1, 2, 3, 4, 5, 6, 7, 8, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20,
1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20,
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 13, 14, 15, 16, 17, 18, 19, 20,
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 14, 15, 16, 17, 18, 19, 20,
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 19, 20,
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 15, 16, 17, 18, 19, 20,
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 16, 17, 18, 19, 20,
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 17, 18, 19, 20,
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 18, 19, 20,
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 19, 20,
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 20,
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
/ select = linked(pic1selector)
</counter>

+++++++++++++++++++++++++++++++++++++++++++++++++++
Definition der Stimuli "Paired Comparison"
+++++++++++++++++++++++++++++++++++++++++++++++++++

<picture pic1left>
/ items = (
/1 = "Audi_A3 Cabriolet_S_Front.jpg"
/2 = "Audi_A4 Avant_S_Front.jpg"
/3 = "Audi_A6 Limousine_S_Front.jpg"
/4 = "Audi_Q7 V12 TDI quattro_S_Front.jpg"
/5 = "Audi_TTS Roadster_W_Front.jpg"
/6 = "Audi_R8 5.2 FSI quattro_S_Front.jpg"
/7 = "SEAT_Alhambra_S_Front.jpg"
/8 = "SEAT_Altea Freetrack_S_Front.jpg"
/9 = "SEAT_Ibiza_S_Front.jpg"
/10 = "VW_Fox_Basic_S_Front.jpg"
/11 = "VW_Golf neu_Trendline_S_Front.jpg"
/12 = "VW_Golf Variant_Trendline_S_Front.jpg"
/13 = "VW_New Beetle_S_Front.jpg"
/14 = "VW_Phaeton_5-Sitzer_S_Front.jpg"
/15 = "VW_Sharan_Trendline_S_Front.jpg"
/16 = "VW_Touareg_V6_S_Front.jpg"
/17 = "Bentley_Azure Cabriolet_S_Front.jpg"
/18 = "Bentley_Continental GT_S_Front.jpg"
/19 = "Bugatti_Veyron_S_Front.jpg"
/20 = "Lamborghini_Gallardo_S_Front.jpg")
/ select = pic1selector
/ position = (25%, 40%)
</picture>


<picture pic2left>
/ items = (
/1 = "Audi_A3 Cabriolet_S_Front.jpg"
/2 = .....
/20 = "Lamborghini_Gallardo_S_Front.jpg")
/ select = pic2selector
/ position = (25%, 40%)
</picture>


<picture pic1right>
/ items = (
/1 = "Audi_A3 Cabriolet_S_Front.jpg"
/2 = "....
/20 = "Lamborghini_Gallardo_S_Front.jpg")
/ select = pic1selector
/ position = (75%, 40%)
</picture>

<picture pic2right>
/ items = (
/1 = "Audi_A3 Cabriolet_S_Front.jpg"
/2 = ".....
/20 = "Lamborghini_Gallardo_S_Front.jpg")
/ select = pic2selector
/ position = (75%, 40%)
</picture>


++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Trials, Blöcke und Likert-Skala (Paired Comparison)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

<likert assoziiert_a>
/ anchors = [1="starke Präferenz"; 4="keine Präferenz"; 7="starke Präferenz"]
/ stimulusframes = [1 = pic2left, pic1right]
/ mouse=true
/ numpoints=7
/ position= (50, 80)
/pretrialpause = 500
</likert>

<likert assoziiert_b>
/ anchors = [1="starke Präferenz"; 4="keine Präferenz"; 7="starke Präferenz"]
/ stimulusframes = [1 = pic1left, pic2right]
/ mouse=true
/ numpoints=7
/ position= (50, 80)
/pretrialpause = 500
</likert>

<block likertassoziationen>
/ preinstructions=(start_exp_teil1)
/ trials = [
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20,
21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60,
61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80,
81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100,
101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120,
121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140,
141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158, 159, 160,
161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180,
181, 182, 183, 184, 185, 186, 187, 188, 189, 190 = noreplace(assoziiert_a, assoziiert_b)]
</block>

...everyone an idea concerning this problem?

regards,

roland

I suggest you re-read this post: http://www.millisecond.com/forums/Topic2511.aspx#2511. Pay special attention to the middle section and the way the two counters are set up. Essentially, you have defined 20 x 19 = 380 pairs (not 190!) in the <counter> elements you posted, i.e. 1-2 and 2-1 are *not* considered identical. Now, when you present a subset of these 380 pairs by running 190 trials, in some cases you'll have both 1-2 and 2-1 among them while other pairs might only occur once, e.g. 3-4 (but not 4-3).

I additionally suggest you change the linked() setting to current(), because the linked() function is considered deprecated. Also, you can simplify the /trials statement to

<block likertassoziationen>

/ trials = [1-190 = noreplace(assoziiert_a, assoziiert_b)

[...]

</block>

Best wishes,

~Dave