The objectives of this research are to find out the correlation between (1) conscientiousness and reading achievement; (2) vocabulary mastery and reading achievement; and (3) conscientiousness, vocabulary mastery and reading achievement.
This research used quantitative method, that is, correlational study. The study was carried out in June 2014 at SMA Negeri 3 Boyolali. The population was all the tenth grade students of SMA Negeri 3 Boyolali consisting of nine classes. The sample was 28 students of class X-4 taken by cluster random sampling technique. The instruments in collecting the data were questionnaire to collect the data of conscientiousness and tests to collect the data of vocabulary mastery and reading achievement. The techniques that is used to analyse the data were Single Correlation and Multiple Regression Correlation.
The results of the data analysis shows that in the level of significance a = 0.05 (1) there is a positive correlation between conscientiousness and reading achievement (rx1y= 0.397 >rt=0.374); (2) there is a positive correlation between vocabulary mastery and reading achievement (rx1y=0.569>rt=0.374); (3) there is a positive correlation between conscientiousness and vocabulary mastery toward reading achievement (Ry12 = 0.657 and Fo= 9.51 >Ft=3.39).
The results of this research also show that conscientiousness and vocabulary mastery are important factors that give contribution to reading achievement. Both conscientiousness and vocabulary mastery have positive contribution to reading achievement that is 43.21%. Thus, conscientiousness and vocabulary mastery should be considered in increasing reading achievement, although the factors are not only variables determining reading achievement.
Keywords: Correlation, Conscientiousness, Vocabulary Mastery, Reading Achievement