The following is from the introduction to Paper Sloyd You will remember that this was written in 1905, when teachers were trained in making observations themselves rather than being dependent on abstract testing procedures.
We are coming to see that the pursuit and attainment by the pupil of a concrete end--some object constructed by him in accordance with a clearly conceived plan--involves a general training as useful in itself and as serviceable in its permanent effect on the pupil as the attainment of a purely intellectual end,--the successful pursuit of a language, the effective grappling with some social problem, or with a problem in natural science or in mathematics, each in its own sphere.The following is from The Pedagogy of Educational Handicraft by T.W. Berry:
Some aver that a course of scientific training in handicraft gives a boy or girl a new zeal for school work to such an extent that the progress of such a pupil is not only equal, but often exceeds, that of pupils whose attention is concentrated on a literary curriculum. If this is true, even to the extent a pupil under these conditions holds his own, he has the additional advantage of having learnt to use his hands, and his education as a result is "all sided." It has been said that "the true aim of education is the development of all the powers of man to the culminating point of action: and this power in the concrete--the power to do some useful thing for man--this must be the last analysis of educational truth"I couldn't have said it better myself!