The phrase "a valid substitute" is correct and usable in written English.
It can be used when discussing an alternative option that is acceptable or meets the necessary criteria in a particular context.
Example: "In this recipe, you can use almond milk as a valid substitute for regular milk if you are lactose intolerant."
Alternatives: "an acceptable alternative" or "a legitimate replacement".
Therefore the use of sheep suppressively treated with effective anthelmintics appears to be a valid substitute for gastrointestinal nematode-free lambs in field experiments.
In a six-page decision rejecting a request from alternative schools for exemption from the Regents exams, Mr. Mills said that the schools could not be excused because advocates had failed to present evidence that portfolios were a valid substitute for the test.
When David Cameron set up the National Citizen Service along with his "big society" initiative in 2011, there was no indication that the NCS would eventually siphon off youth service budgets: this four-week summer citizenship scheme cannot be considered a valid substitute for year-round youth provision.
This was again important for simplification of future protocols as arterial cannulation could be omitted if venous sampling was proven to be a valid substitute.
In the past few years, collagen matrices (CM) have been studied as a valid substitute for free gingival grafts, in particular the porcine CM Mucograft (Geistlich Biomaterials GmbH, Baden-Baden, Germany).
There are a number of reasons for this; firstly the electromagnetic spectrum is becoming over-congested and hence the use of acoustics can become a valid substitute in situation where long range detection is not a tight requirement.
It's apparently a very old idea going back thousands of years, and we know that in pseudoscience circles age is a perfectly valid substitute for "evidence that is actually works".
Poly vinyl alcohol) (PVA): it is selected for its good optical properties making it a valid vitreous substitute; it is indistinguishable from the vitreous during the initial months following injection.
It is also important to determine if NR could be valid substitute to avoid undesirable side effects of other NAD+ precursors such as NA and NAM, for instance when used as lipid lowering drugs [15, 59].
Expression filters are useful to assess 'magnitude of effect' and to reduce the number of comparisons for a subsequent statistical test, but they are not valid substitutes for formal statistical testing.
Consequently, the cotton, abaca, and silk model textiles were found to be valid substitutes for historic iron-tannate dyed textiles in stabilisation treatment studies.
