This number (1,153,442) makes up 11.6 percent of Hungary's population, which is a sharp drop of 28.2 percent from the last census' reports of 1.6 million Reformed people (17.8 percent) in 2001. In fact, there was a decrease in religious affiliation across the board. The numbers for the Roman Catholic Church also showed a significant decrease of 34 percent from 5.5 to 3.8 million.
The number of Hungarian citizens without a religious affiliation (1,806,409) on the other hand, increased from 14.5 percent to 18.1 percent, while those who abstained from answering the question of religion also had a dramatic increase from 10.8 percent in 2001 to 27.1 percent in 2011.
According to Ádám Hámori, sociologist, assistant professor at Károli Gáspár University of the Reformed Church in Hungary and Ph.D. student at Corvinus University of Budapest, the changes evidenced in the 2011 census. First of all, there were a few optional questions posed in the questionnaire, including the question of denominational belonging. Therefore, any evaluations from this data should be done cautiously. Considering the number of people that did not answer the question of religion, some 2.7 million, a representative sample of the population would have presented far more accurate data.
The 2011 census, according to Hungarian state regulations and in conformity with EU methodology expectations, utilized a "mix-mode" method approach to collecting data. The 2001 census operated solely on face-to-face survey technique, while the 2011 census also included self-administered questionnaires that could be submitted either online or through the mail. The nature of the mix-mode collection method is in itself less reliable than other modes and leaves data bias uncontrollable. However, it has proven to be effective in increasing response rates.
Furthermore, Hámori said that aside from the huge number non-responses, there was a change in the wording of the question that makes comparing the respective census data unfounded. The question in 2001 asked, "What is your religion, denomination?" For the 2011 census, the optional question asked, "Which religious group or denomination community do you belong to?" This is not to say that the change in wording was a cause in the decrease of religious affiliation, but instead, we cannot know the extent to which the wording affected the resulting data.
This drop in religious identity is a major concern for churches throughout Europe, and communicates what Hámori calls "an ongoing generational change in Hungary." He mentions a phenomenon American sociologists describe as "religious markets" where churches are seen as suppliers that must compete in a "religious market" for members. And while the census data may be incomparable or unreliable concerning the question of religion, it should forewarn churches and steer them to the necessity of structural modernization.