School head formulates first dataset, preparing it with firm resolve (9)

I believe the answer is:

steadfast

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'school head formulates first dataset preparing it with firm resolve' is the definition.
I can't tell whether this defines the answer.

'school head formulates first dataset preparing' is the wordplay.
'head' indicates taking the first letters.
'formulates first' becomes 'f' (1st letter of 'formulates').
'preparing' is an anagram indicator (the same letters prepared differently).
The initial letter of 'school' is 's'.
'f'+'dataset'='fdataset'
'fdataset' is an anagram of 'teadfast'.
's'+'teadfast'='STEADFAST'

Can you help me to learn more?

(Other definitions for steadfast that I've seen before include "Fixed, unyielding" , "Strong" , "Firm, fixed and faithful" , "Resolute, unwavering" , "Resolutely firm" .)

I've seen this clue in The Irish Times.

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