Most biomedical information extraction (IE) approaches focus on entity types such as diseases, drugs, and genes, and relations such as gene-disease associations. In this paper, we introduce the task of methodological IE to support fine-grained quality assessment of randomized controlled trial (RCT) publications. We draw from the Ontology of Clinical Research (OCRe) and the CONSORT reporting guidelines for RCTs to create a categorization of relevant methodological characteristics. In a pilot annotation study, we annotate a corpus of 70 full-text publications with these characteristics. We also train baseline named entity recognition (NER) models to recognize these items in RCT publications using several training sets with different negative sampling strategies. We evaluate the models at span and document levels. Our results show that it is feasible to use natural language processing (NLP) and machine learning for fine-grained extraction of methodological information. We propose that our models, after improvements, can support assessment of methodological quality in RCT publications. Our annotated corpus, models, and code are publicly available at https://github.com/kellyhoang0610/RCTMethodologyIE.