Example datasets for bep036

[Arshitha]

Added pheno001 and pheno002 example dataset inspired by ds004215 on OpenNeuro but significantly modified to keep it simple and easy to convey the various use cases proposed in BEP036.

Use cases covered (and to be added to this PR):

• pheno001 - Single session with both phenotype and imaging data
• pheno002 - Two sessions with one imaging data only session
• pheno003 - Two sessions with one phenotype data only session
• pheno004 - Two sets of sessions. One set of sessions (e.g. screening, baseline, followup, etc) for phenotype data and another set of sessions (e.g. 01, 02, etc) for imaging data.

Still in draft state but would appreciate any and all feedback.

Pinging co-contributors: @ericearl @SamGuay @surchs

[ericearl]

This is great, thanks! I'm guessing you left it in draft state becausew of pheno001 and pheno002, right?

I think we should remove the age_at_visit column/field from all phenotype/ measurement tools and instead provide a root-level sessions file with that field. Should we maybe take that a step farther and RECOMMEND or say it's OPTIONAL to add age to the sessions file?

[Arshitha]

I like that idea. It's redundant information that can be aggregated to sessions level, and can be a recommendation in the BEP.

[Arshitha]

It's in Draft state because I haven't prepared pheno003 and pheno004 but yes, all four example datasets will violate the contribution guidelines.

[ericearl]

Suggested change

	"age_at_visit": {
	"age": {

[Arshitha]

In this case, age_at_visit would be the same as age and that's the reason I changed it to age_at_visit.

[ericearl]

I think it's still fine to keep as age, but I would let @SamGuay and/or @surchs be the tie-breakers.

[ericearl]

Suggested change

	participant_id sex age_at_visit MRI ace demographics
	participant_id sex age MRI ace demographics

[Arshitha]

same as previous comment

[christinerogers]

Got a question from @dominikwelke --

Could this PR include an example showing how to represent multiple runs from one participant-session?

@ericearl mentioned today this is easily done by adding a run column in the .tsv, would be nice to see illustrated and mentioned here.