With limited formal education, Poerbatjaraka was largely an autodidact.
Early in his career, he was criticized as "amateurish", and lacking a "scholarly accurateness".
According to the Javanese literature scholar Th.
Pigaud, he made up for this with his extensive knowledge of Javanese literature, of all things Javanese in general, and by his zeal for Javanese studies.
As he matured, he gained respect among both Europeans and his fellow Indonesians.
His works combined the scientific method—which was uncommon among Indonesian native authors at his time—with his intimate knowledge of his subjects as an insider.
He was often critical of the text and manuscript that he worked on, noticing spelling errors, and preferring to compare multiple sources before publishing a manuscript.
Pigeaud said that his works and his behaviour often showed a sense of humour characteristic of a punokawan (jesters in Javanese wayangs).
During his retirement in Jakarta, he did not stop working.
De Graaf said that during this period he was "quietly but indefatigably studying and publishing".

According to his biography by Indonesia's Education and Cultural Ministry, he published seventy-nine works throughout his life, while Pigeaud put the number at seventy-three.
His works focus on epigraphy of old Javanese literature.
They were written mostly in Dutch and, after Indonesia's independence in 1945, he also wrote in Indonesian and Javanese.

Among his notable works, he published studies on Agastya, the Old Javanese works Smaradahana, Arjunawiwaha, Ramayana and, with C. Hooykaas, the Bharatayudha.
His study on the Ramayana established that, based on language, metrics, titles of officials and description of a temple, the Old Javanese version of the epic poem originated at the end of the ninth or the beginning of the tenth century.
This finding was later confirmed by other studies, including one by Hooykaas.
Later in his career, he published Kapustakan Djawi ("Javanese Literature"), which surveyed eighty-four old and modern Javanese literary works.
He also published what he intended to be the first volume of Riwajat Indonesia ("The History of Indonesia"), covering the country's history up to the eighth century.
No further volume was published until his death.
With limited formal education, Poerbatjaraka was largely an autodidact. Early in his career, he was criticized as "amateurish", and lacking a "scholarly accurateness". According to the Javanese literature scholar Th. Pigaud, he made up for this with his extensive knowledge of Javanese literature, of all things Javanese in general, and by his zeal for Javanese studies. As he matured, he gained respect among both Europeans and his fellow Indonesians. His works combined the scientific method—which was uncommon among Indonesian native authors at his time—with his intimate knowledge of his subjects as an insider. He was often critical of the text and manuscript that he worked on, noticing spelling errors, and preferring to compare multiple sources before publishing a manuscript. Pigeaud said that his works and his behaviour often showed a sense of humour characteristic of a punokawan (jesters in Javanese wayangs). During his retirement in Jakarta, he did not stop working. De Graaf said that during this period he was "quietly but indefatigably studying and publishing". 
According to his biography by Indonesia's Education and Cultural Ministry, he published seventy-nine works throughout his life, while Pigeaud put the number at seventy-three. His works focus on epigraphy of old Javanese literature. They were written mostly in Dutch and, after Indonesia's independence in 1945, he also wrote in Indonesian and Javanese. 
Among his notable works, he published studies on Agastya, the Old Javanese works Smaradahana, Arjunawiwaha, Ramayana and, with C. Hooykaas, the Bharatayudha. His study on the Ramayana established that, based on language, metrics, titles of officials and description of a temple, the Old Javanese version of the epic poem originated at the end of the ninth or the beginning of the tenth century. This finding was later confirmed by other studies, including one by Hooykaas. Later in his career, he published Kapustakan Djawi ("Javanese Literature"), which surveyed eighty-four old and modern Javanese literary works. He also published what he intended to be the first volume of Riwajat Indonesia ("The History of Indonesia"), covering the country's history up to the eighth century. No further volume was published until his death.
Poerbatjaraka