Full Idea
During the decade after 'Problems of Philosophy' Russell points our repeatedly that specifications of sense-data come last in analysis, not first in experience.
Gist of Idea
After 1912, Russell said sense-data are last in analysis, not first in experience
Source
report of Bertrand Russell (Problems of Philosophy [1912]) by A.C. Grayling - Russell Ch.2
Book Reference
Grayling,A.C.: 'Russell' [OUP 1996], p.43
A Reaction
This was a symptom of Russell losing faith in sense-data, and he eventually abandoned them. There is a possible position where we deny any such item as sense-data in a scientific account, but allow them in our metaphysics.