The phrase "approach was previously" is correct and usable in written English.
It can be used when discussing a method or strategy that has been used in the past.
Example: "The approach was previously employed in similar studies to achieve reliable results."
Alternatives: "method was earlier" or "strategy had been previously".
Though this approach was previously attempted during the Clinton administration, evidence shows that it did not create meaningful improvement in the lives of those affected.
This approach was previously found to be useful for developing detailed and semi-detailed mechanism of oxidation of various hydrocarbon fuels.
For the case of a dike subjected to a rapid drawdown of the current water level, a Monte-Carlo based approach was previously employed.
While this approach was previously shown to be extremely effective when implemented with community volunteers outside of school, the objective of these new scale-up evaluations was to develop a model that could be implemented within the government school system.
This approach was previously successfully applied on the recognition and monitoring of other food/spoilage bacteria tested in similar experiments [31, 33].
The same approach was previously adopted to detect co-seismic and magma-migration-induced gravity changes (Tanaka et al., 2001; Furuya et al., 2003).
Details of the approach were previously published [65].
This approach is previously referred to as the full-screen approach (Sheiner and Benet, 1985).
Similar neoantigen-targeted vaccine approaches were previously tested6,7 in early-phase clinical trials for melanoma, which, unlike glioblastoma, is a type of cancer that has a high level of mutations and neoantigens.
Posterior, transabdominal, and combined approaches were previously reported for the surgical resection of presacral tumors.
Details of all constructs and approaches were previously reported [7], [8].
