"not underpinned" is a perfectly correct and usable phrase in written English.
It means that something is not supported or strengthened by something else, and can be used in many different contexts. For example, "This argument is not underpinned by any credible evidence."
It is not underpinned by legislation but, in the self-regulatory sense, takes a voluntary approach.
The IFLA's scheme is not underpinned by statute: it seems to be an entirely private initiative.
It hid behind over-optimistic assumptions about "efficiencies", which were not underpinned by serious analysis, and soon unravelled.
The euro gave these countries access to cheap credit, which was used to finance wage increases that were not underpinned by productivity gains.
Any attempts to restore democracy are prone to disruption if they are not underpinned by a deeper process of national reconciliation.
Even though it has expanded over the years, this gave a misleading impression of progress if the banks were not underpinned by institutional safeguards to prevent excessive and imprudent lending.
Such an approach does not underpin national curriculum documents to the same extent.
Early postoperative reorganization to ipsilateral posterior or contralateral medial temporal lobe structures does not underpin better performance.
However, we were unable to detect any gene expression of Pgr in the testis at d 80, suggesting that direct action by progesterone does not underpin this phenotype.
In order to provide further evidence that activation of NPR2, and consequent increases in cellular cGMP concentrations do not underpin the effects of CNP on RAoSMC and HUVEC, cGMP levels were measured in both cell types.
This does not underpin our finding that women's use of psychiatric specialists decreased by age, but substantiates our study regarding the relative use between genders since utilisation rates for men and women approached in higher ages.
