"methodological deficiencies" is correct and usable in written English.
You can use it to refer to issues or weaknesses in a research method or methodology. For example: "The study was hampered by several methodological deficiencies, such as an inadequate sample size and lack of control group."
Methodological deficiencies are defined as an inappropriate methodology of the indirect comparison, as for example heterogeneity of study results within MTC, non-similarity of studies, inconsistencies of outcomes of comparisons.
Many of them are marked by methodological deficiencies, preconceived ideas, and a prejudiced selection of source documents; nevertheless, some of these theories contain points of view that deserve consideration.
The Democrats say Mr Obama's ahead in the key states; the Republicans counter that the national polls are tied, and that the state polls suffer from unsubstantiated assumptions and methodological deficiencies.
"Unfortunately," he concedes, "no one really knows the answer," and he says of the studies that purport to provide an answer that they are often not "relevant to the teaching of undergraduates" and "almost always suffer some serious methodological deficiencies".
Ideally, this study should be replicated without the above confounding variables and methodological deficiencies.
Most of the studies suffer from the methodological deficiencies discussed above.
Indirect land use changes are recognised but not included due to current scientific and methodological deficiencies.
Reasons for rejection of indirect comparisons by IQWiG can be classified in either formal or methodological deficiencies.
Heterogeneity and methodological deficiencies in the studies prevented conclusions regarding stage of palate repair and facial growth.
Third, the decisions of IQWiG were analyzed whether the indirect comparison was accepted or rejected and reasons for rejection were identified and classified in formal or methodological deficiencies.
This is necessary to be able to learn of methodological deficiencies and acquire new methods to address heterogeneity and biases within indirect comparisons.
