I'm not sure what you mean by "validate," since that term is usually associated with quantitative research, in these of whether or not you have an accurate conclusion. Since qualitative research is more interpretive, there is always going to be an influence of your own subjective judgment.

Within qualitative research, this issue has been debated quite a lot, with some of the best known work falling under the heading of "credibility" (i.e., believability) rather than validity. The source for most of that work is Lincoln and Guba's 1985 book Naturalistic Inquiry.

Here is a link that provides more in-depth information on the criteria that Lincoln & Giba propose:

http://www.qualres.org/HomeLinc-3684.html

I agree with the suggestion to look at Lincoln and Guba's work for guidance.

I also agree with the comment about use of the term "validating" because participative qualitative research is aligned with a constructivist philosophy where research is concerned more with contextualised, subjective knowledges. Validity in this sense has a very different meaning compared to positivist philosophies For research to be seen as "valid" in positivist research it is implied that it has some level of temporal stability (i.e. relevant and stable over time) and some level of generalisability (i.e. relevant to other related or similar contexts), contributing to a reasonable expectation that the research findings could be replicated by others. In contrast, research of the kind you describe is likely to be dynamic (i.e. low temporal stability) and very contextually specific (i.e. related to this group, these people, this circumstance). For this reason, concepts such as plausibility, credibility, coherence are usually more relevant than validity. 

If what you are looking for is plausible findings that you can confidently use to inform  action, based on the limited information provided, you may look to triangulate your research by looking at the data emerging from different sources and perspectives: the findings from interviews, compared to the data emerging from the co-creation and co-design workshops, compared to other sources of data such relevant literature, quantitative data, other reported research and so on.

The idea of validity starts with the rigour applied in your research process - the choice of methodology and underlying ontological and epistemological assumptions; the research design and execution of the research design; who is involved and who is not; the way that diverse views and data are managed; the critical engagement with the data; how and who is involved in sense-making and interpretation of data. All of these (and more) are factors that I think relate to notions of validity as it relates to qualitative research.

Thanks a lot David and Vicki, your explanations are very valuable. I totally agree with both of you.....in my research I have collected data from children  using art based activities (e.g creating models and drawings) and the initial analysis of children's workshops have used for further data collection for parents  and then to medical staff workshops.  I will compare the  findings with literature and also I have a workshops with four groups of designers in which they discussed the implication of such a data.  I analyzed every workshop alone, then a cross analysis between the nine workshops have been done. I think all these steps  will help to construct the credibility and the rigour in my research.

Thanks David for the link I will have a look

The steps you describe are all good contributions to the trustworthiness of your conclusions, and they would be as much as (or more than) I would expect for a thesis or journal article.

One other concept from Lincoln and Guba that you might consider is "transferability," which is their alternative to generalizability. The key question there is the range of other settings where you results might apply. In other words, who else might benefit from thinking about the things you have learned.

Many thanks David, that is is also will be done. I have six key questions beside the main research question and I figure out the results if they can answer my key questions or not, but I think they are.......thanks again your explanation open my mind to construct my ideas for the chapter of discussion......

If you will be building something, such as a user interface, based on your participatory research, you can do some early usability evaluation of your user-interface design using paper prototypes.  It would help to know whether your participants were children or adults.

Many thanks Elizabeth, because I have funding just for three years, I think I just will draw out patterns, strategies, may be framework and design consideration. My participants are from children 3-18 years, and from parents , medical staff, and I have designers as well. I'm now nearest to finish the third year and still in data analysis which I have started since 7 months. The implication at the end will be on both macro level and micro level....

Since you are using children as participants, you might do well to look at related work by Juan-Pablo Hourcade and Alison Druin.  If you want me to look up specific references, I'd be happy to do that.

Thanks a lot Elizabeth D.Murphy, actually I didn't remember if I read about their work, please if there is specific work can be beneficial in my case, it's great pleasure for me to read that

Juan Pablo Hourcade has published "Child-Computer Interaction," which is available free at childcomputerinteraction.org.  Alison Druin edited "The Design of Children's Technology" (1999), published by Morgan Kaufmann.  You might be interested in Druin's co-authored article:  Muller, M. J., & Druin, A. (2011). Participatory Design: The third space in HCI. In J. Jacko (Ed.) The Human-Computer Interaction Handbook (3rd ed., pp. 273-291). New York, NY: Taylor & Francis.

Thanks a lot Elizabeth, it seems I read some of them in my first years  before I collect my data, i will have a look another time,

I appreciate your cooperation and efforts

It sounds as if you are doing something related to design research and/or action research. Gillian Hayes has a good discussion of action research in HCI

Hayes, G. R. (2011). The relationship of action research to human-computer interaction. ACM Transactions on Computer-Human Interaction, 18(3), 1–20. doi:10.1145/1993060.1993065

A key question is to triangulate your interpretation of what is going on with the views of other participants / stakeholders - who may see things differently.

In the UCHD project we have been investigating how to rigourously evaluate design research activities.

Here's a couple of pointers -

Bowen, S., McSeveny, K., Lockley, E., Wolstenholme, D., Cobb, M., & Dearden, A. (2013). How was it for you? Experiences of participatory design in the UK health service. CoDesign, 9(4), 230–246. doi:10.1080/15710882.2013.846384

And a paper at the Design Research Society conference:

http://www.drs2014.org/media/647964/0161-file1.pdf

There are quite a few references in those two papers that are worth following up. If you have difficulty obtaining these, let me know and I will try to help. My own work should be available in open access - look on shura.shu.ac.uk

Another question to consider is whether you are seeking to evaluate/improve your design methodology, or whether your core aim is to evaluate the quality of the outputs (in terms of health recommendations or interventions). From a methodological point of view, take a look at:

Doerflinger, J., & Dearden, A. (2013, September 10). Evolving a Software Development Methodology for Commercial ICTD Projects. Information Technologies & International Development. Retrieved from http://itidjournal.org/index.php/itid/article/view/1089

Thanks a lot Andy Dearden, your response is valuable. According to the  key question, yes it is "to triangulate your interpretation of what is going on with the views of other participants / stakeholders - who may see things differently".

Regarding whether I'm seeking "to evaluate/improve your design methodology, or whether your core aim is to evaluate the quality of the outputs (in terms of health recommendations or interventions). From a methodological point of view " I think both.

Related to action research, I think in my case it is not action research. The data analysis highlighted important issues related to culture issues. I did nine workshops in Palestine, my participants are children from 3-18 years old, parents, doctors, nurses, reception areas employes and  another workshop with four groups of designers also conducted in Palestine. In addition to that, I have 3 individual meeting with two Civil engineers, and one meeting with a manger of the admission area in one of the hospitals in Palestine. My abstract and poster for the conferences in my account can give you an overview of my research.

I will have a look on both articles....Thanks a gain

Hi Rawa,

Looks like you have a lot of valuable input from other professionals. I was just drawn to your question as my dissertation is employing a comparable methodology. I am also doing a project with kids and young adolescents using a mix of draw and write technique and interviews. 

I get the sense that you are doing a research that involves spaces. If so, Alison Clarke's book on the Mosaic approach maybe worth having a look. Her book is called: Listening to Young Children: The Mosaic Approach. 

From the thread, maybe you just need to reflect whether your study can be really called participatory in its true sense. Participatory action research is different from qualitative exploratory. The exploratory bit is usually the beginning of a multi-stage process common in participatory action research. 

Many thanks Harry. for you comments......Yes I think I read this book in my second year before collecting my data. According to my research methods, yes it is as I defined it in my conferences papers. I used multi methods with all of my participants, they create drawings, models, they write and record their views through  interviews ( focus groups) etc., I have a rich data, and spending much time until defining it....because I used co-design and  co-creation that is the reason I defined it as a participatory....

Yes I used it  for designing public spaces  for  a new children's hospital in Palestine,