The most common and most likely answer to this crossword clue is the 3 plus 5 plus 2 plus 1 plus 4 letter word ONE THING AT A TIME
I've seen this crossword clue in The Daily Telegraph
O
N
E
T
H
I
N
G
A
T
A
T
I
M
E
More clues leading to the result ONE THING AT A TIME
Buddy explains!
The straight part
We know that "demand for measured progress" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case demand for measured progress = one thing at a time.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.