I feel when it comes to any volunteering you can’t really measure the impact, at least not fully in a quantifiable way. The same is with skills based volunteering. With any of the skills based volunteering you can quantify their impact by what they have created, for instance homes or playgrounds. These physical items can be used to quantify the volunteering impact by stating how many people use it now that ti is there or how many people have been helped due to this act of volunteering.
However, I feel that even if you somehow quantify the impact, you are only really quantifying maybe half of the impact. The rest is purely emotional or things that numbers can’t describe or measure. You can maybe measure the impact with words, but truly it is something you experience, it is something you watch grow, you live in the action of the impact and each person measures it differently. That is what makes volunteering so unique and special is that its impact is felt, not measured.