"valuable predictor" is correct and usable in written English.
You can use it when you want to express that something or someone can give a reliable indication of what something else may be like. For example, "The results of the survey proved to be a valuable predictor of public opinion on the issue."
"It's not a kind of speech that's a valuable predictor of one's capacity to govern," she said.
If enough traders participated in the market, it would become, in the long run, a valuable predictor of housing prices in different cities.
Isolation was also a valuable predictor of species occurrence, especially for forest specialists.
Maximal bladder capacity is a valuable predictor of response to desmopressin.
It appears to be a valuable predictor of the success of UPPP.
Correlating the ocular physiology with the physicochemical characteristics of acyclovir ophthalmic ointment suggested that in vitro quality metrics could be a valuable predictor of its in vivo performance.
Prior studies have shown lactate clearance to be a valuable predictor of patient outcomes, however some have defined adequate change in lactate by a decrease from baseline by 10% whereas others considered an absolute reduction to lactate < 4mmol/L.
Slope and distance to the nearest path were also identified as valuable predictors.
Abnormal fetal assessment tests are valuable predictors of antepartum fetal asphyxia.
In clinical practice, immunohistochemistry on tissue biopsies and ELISA-based detection of circulating SCCA (including both SCCA1 and SCCA2) are currently used as valuable predictors of nodal metastasis, response to treatment, and tumor recurrence in SCCs of the uterine cervix, lung, head and neck, esophagus, and liver [5], [6].
Certain specific AEs may be valuable predictors and biomarkers of treatment efficacy, although further prospective investigation is warranted.
