do a super-complex randomization?

Hi,

I want to present the following questionnaire, there's 3 levels of randomization in there and I can't get my head around how to do this:

1. for each participant we want to present 30 pictures in a random order
2. each of the 30 pictures has 8 captions (we want to cluster the captions per picture, so the participant sees the 1st picture with the 8 captions, then the 2nd picture with the 8 captions etc.) - we want to present the captions in a random order for each participant per picture
3. for the 8 captions we want to present there is more than 1 for each to choose from (e.g. for the 1st caption there is 4 to choose from, for the 2nd caption there is 9 to choose from etc.). for each of the 8 captions we want to chose one caption randomly (out of the various captions that exist for each caption), this has to be done randomly for each participant, too.

Can MediaLab handle things that are so complex? any help would be greatly appreciated! Thanks

To be sure I'm clear here, I'm going to try and paraphrase. Please let me know if I've got it!

You need 8 captions per picture. Caption1, Caption2, ..., Caption8. These captions are constant for all of the images but will be presented/arranged in a random order for each of the 30 images.

Selecting the Captions:

Each caption is randomly selected from a specific set designed for it so, e.g.,

Caption1 will be chosen randomly (assuming [I]with replacement[/I] here since it is only done once for each set) from a set such as Caption1a, Caption1b, Caption1c, Caption1d.

Caption2 will be chosen randomly from a set such as Caption2a, Caption2b, ..., Caption2i.

Then, once the 8 constant captions have been determined and then randomly ordered for each image, we randomly order the 30 images for presentation.

Yes? No?

Thanks for the quick reply:

yes, I think your re-phrasing almost works with what I'm trying to do -

we need 8 captions per picture (Caption 1, Caption 2, Caption 3... Caption 8), BUT they are constant for EACH of the 30 pictures, so every picture has a set of different captions to choose from (so I guess they are NOT constant for all the images?).

re selecting the captions:
yes, the 1st caption will be randomly chosen from a subset 1a through to 1x same for the 2nd caption (chosen from a subset 2a-2x) up to the 8th cation (chosen from a subset of 8a - 8x) - the number of captions for each of the 8 subsets however varies (sometimes it's only two, sometimes it's nine..).

The last step: yes, once the 8 captions have been determined & randomly ordered for each image we randomly order the 30 images.

any advice welcome!!!

Got it. One more question--are you repeating the presentation of the images? E.g., will they see image #17 more than once? If so, will the captions need to be the same (in content and order) as they were the first time #17 was shown? Or are you looking at just 30 trials and they're done?

The trials won't be repeated. participants only see each of the 30 images once (which is actually 8 times since they see the picture and 1 caption, make a rating about the caption, then see the same picture again with a 2nd caption, make a rating about the caption etc. up to the 8th caption, then they see the 2nd of the 30 images 8 times), so in total participants have to make 240 ratings.

is it possible to present the instructions, followed by the caption, image and rating scale on the same page?

Thanks for your help!

OK, short answer, no, MediaLab can't really do this unless you want to get into custom items and some javascript programming to handle a bit of this work. I can elaborate on that but let me first ask if you access to DirectRT. I ask because DirectRT could do this pretty easily and I could get you started on the way to do this, but if it needs to be MediaLab it's a possible success but again a very different discussion!

Thanks for that! No - no access to Diretct RT. I've started customizing the questionnaires for each participant as this is the only way I could think of, not using Java though (I'm not really a programmer). I am not sure yet how much work the way I'm trying to do this will be - it seems like a fair bit.

would it be quite hard for me to get into Java without any experience?

Thanks!