Identification by name
          The first difficulty arising during detection and processing of data from the archives starts with the fields regarding the "name" and "surname". Thus, there are many cases where the same person appears in documents with multiple surnames and first names.
          In the early 1950s, many activists of the Communist Party from the interwar period have "Romanianized" their names and surnames. Therefore, the documents hold both their names. For example - Iosif Adler changed his name into Iosif Ardeleanu. In another situation - some militants frequently used their codenames from their illegal times, so that their birth name could be found only after more complex investigations. For example, Aaron Lazar (birth name), became known in the history of communism by the name of Alexander Buican (changed name). However, this person often appears in documents with different conspiracy names, of which the best known is Ernst Arnoldi. Aaron Lazar, Ernst Arnoldi and Alexander Buican actually represent the same person. Even more difficult is to identify correctly the name of women militants, who changed the name after marriage.
          For example, the militant woman Haia Hutschneker (birth name) became Haia Moscovici after marrying Ghelbert Moscovici. Ghelbert Moscovici is known in the illegal communist movement by the name of Alexandru Bădulescu and his wife frequently appears in the party documents with the name Ana Bădulescu (borrowing her husband's codename). Therefore, consulting additional sources, initially unforeseen, was needed in order to clarify the nominal track of the most representative RCP leaders.
 
Ethnicity
          Nationality is another seemingly easy to summarize criterion, but, however, it involves some difficulties. For instance, militants in Transylvania with Hungarian names declared to be Hungarian ethnics in their overwhelming majority. In some cases known the real ethnic origins can be identified, but for most it is difficult to know the family history.
          In some high profile cases, the real ethnic origin could be identified, but for most it is difficult to reveal their family history. Other militants, known as belonging to other nationalities, have declared themselves in documents as Romanians. Regarding the parameter of "ethnicity”, two possibilities were available to identify a single criterion: either recording ethnicity as it was assumed by each subject, or correcting the archival source by corroborating with other research data.  The first option was chosen for several reasons. First, the modern meaning of nationality was preferred (you are what you declare yourself to be); on the other hand, the considerable number of subjects ​​at this moment made verifying each of them quasi-impossible.
 
Party experience
          Another observation that took shape during the study concerns the underlying parameter of the analyzed group, which is the membership of the underground Communist Party. The documents after 1944 define it as “underground party internship” and it relates to the year when a person became a RCP member. The difficulty of registering this parameter arose when it was discovered that different sources offer different dates for the same individual. There are two kinds of inadequacies: either the documents recorded different years before August 23, 1944 for the same individual, or they recorded a year before and one after 1944.
          A number of explanations emanate when studying in detail the illegal party’s internal life. The inconsistencies are justified by an extremely low degree of formalization regarding the inner party life during its underground times. Thus the membership in the Communist group was not validated by documents (membership card, ID card, records of members etc.). Obviously, at the end of its underground activity, (August 23, 1944), the party did not have any records, be they vague and incomplete, regarding the number of members, nor archives and statistics on the preceding 20 years.
          Under these circumstances, both the underground members’ activity and party experience was reconstituted individually using a mechanism perfected in the first years after August 23, 1944. The “illegalist” wrote an autobiography with a predefined content. Among other things, he declared, "on his own responsibility", the year when he joined the Communist Party. For every stage of his life he named a number of people who could certify the truthfulness of his statements. However, the simple declaration of membership to the RCP – by an individual or by referents- was a necessary condition, but, not sufficient.
          The Staff Section and Central Party College’s analysis committees took other criteria into account. For instance the actual activity, continuity, loyalty to the group tested through the pre-war arrests, investigations and trials and also his behavior after August 23, 1944 were important for granting "underground party internship" status.
          The deliberations of these analysis committees could lead to inaccurate conclusions. For instance, people known from previous researches of the project manager  as unquestionably belonging to the main leadership of the illegal Communist Party, appear in the archives as holding party membership from 1945, 1946 or even later (ex. Gavril Birtaș). Thus, by strictly examining the documents, it appears that some people haven’t been members of the party even though other sources mention them as leadership members!
          Processing data using this criterion is complicated because during the communist regime, "the party experience" was an extremely dynamic parameter. It was changed by general political grounds, some directly related to the person in question, some depending on internal developments of the regime. A consistent triage was performed during 1948-1950 when the “party asset” was verified. Subsequently, cases have been reviewed, in general at the initiative of the persons in question, who had a pecuniary motivation: an internship during the underground period of the party entitled them to rewards proportional with their party experience. At the Ninth Congress of the RCP in 1965, an important number of old campaigners were deemed "illegalists".
          In this research the section "year of joining the party” used a mixed criterion. Generally, the year recorded in the file of the “illegalists” was used, but, however, in notorious cases, the year was corrected by analyzing other sources.