1.公民接受基础教育的比例。2.权力机构受到多大的约束。3.司法是否具备独立性 4.民主历史。 5.公民里信仰新教的比例，等等

都是相关因素

GDP倒不在列。

还有一个是和语言相关的： 

 ...languages which do not permit the dropping of first person pronouns (e.g., “I” in English or “ich” in German) serve to demarcate an individual from his or her social context, in turn reinforcing values around individual autonomy and responsibility. We found a strong positive correlation between reporting rates and countries with languages which do not permit the dropping first personal pronouns...