The phrase "a scale which was" is correct and usable in written English.
It can be used when describing a specific scale that existed or was in use at a certain time in the past.
Example: "The researchers analyzed a scale which was developed in the early 20th century to measure intelligence."
Alternatives: "a scale that was" or "a scale which existed".
"The ability now to hoover up, analyse, discard, process information is now on a scale which was unimaginable even a few years ago.
By their former tariff the duties imposed on our manufactures were on a scale which was subject to gradual reduction, and in 1840 the rates had become comparatively moderate.
Microarray technology offers the potential for mass screening of compounds on a scale, which was once unimaginable.
The subjects also responded to a scale, which was designed to measure degree of technological influence and provide a score for each respondent to reflect how highly they were influenced by technology in the work units of their hospital.
"We cannot operate this American machine," reasoned Filene during the debate over the National Labor Relations Act in 1935, "...unless the masses can buy on a scale which was never before heard of".
For example, in a scale which was designed to measure tendency to become depressed, an item about general lack of motivation would most likely be endorsed more readily than an item indicating suicidal ideation.
This, roughly, is what happens: Auto-Tune locates the pitch of a recorded vocal, and moves that recorded information to the nearest "correct" note in a scale, which is selected by the user.
The fact that people still buy books on a scale which is a fond memory in the record industry may explain the current cascade of rock memoirs, from Rod Stewart to Tim Burgess.
Each map has a scale, which is a relative measure of the units of distance on the paper that map onto the real-world environment.
The MRS is a scale which is widely used to assess the symptoms of the menopause.
It has been shown that a scale which is balanced towards higher categories is more likely to provoke an apparently higher response level [ 19, 20].
