Derya Çobanoğlu Aktan

Bu çalışmada öğrencilerin sosyoekonomik durumu, matematik öğrenmeyi sevmeleri, okullarının akademik başarıya verdikleri önem ile öğrenci matematik başarısı arasındaki ilişki çok düzeyli yapısal eşitlik modeliyle (ÇDYEM) incelenmiştir. Araştırmada örneklem TIMSS 2011 çalışmasına katılan Türkiye’deki 5960 sekizinci sınıf öğrencisidir. Araştırma bulguları öğrencilerin matematik başarı varyansının %33’ünün okullar arası farklılıklardan, %67’sinin öğrenciler arası farklılıklardan kaynaklandığını göstermiştir. ÇDYEM’de, öğrenci düzeyinde öğrencilerin sosyoekonomik durum ve öğrencilerin matematik öğrenmeyi sevmeleri, okul düzeyinde yine sosyoekonomik durum ve okullarının matematik başarısına verdiği önem yer alarak her iki düzeyde de bu değişkenlerin matematik başarısıyla ilişkisi modellenmiştir. Bulgulara göre sosyoekonomik durumu yüksek olan öğrencilerin bireysel başarıları; dolayısıyla bu öğrencilerin bulunduğu okulların ortalama başarıları diğer okullara göre nispeten daha yüksektir. Okul düzeyindeki sosyoekonomik durumun okulun akademik başarıya önem vermesini pozitif yönde etkileyerek okulların daha yüksek başarıya sahip olmalarına katkı sağladığı görülmüştür. Ayrıca, matematik öğrenmeyi seven öğrencilerin daha yüksek matematik başarısına sahip olduğu bulgusuna ulaşılmıştır. Son olarak, araştırma bulgularına dayanarak eğitim politikaları kapsamında önerilerde bulunulmuştur.

This study has two main purposes. Firstly, to compare the different item selection methods and stopping rules used in Computerized Adaptive Testing (CAT) applications with simulative data generated based on the item parameters of the Vocational Maturity Scale. Secondly, to test the validity of CAT application scores. For the first purpose, simulative data produced based on Vocational Maturity Scale item parameters were analyzed under different item selection methods (Maximum Fisher Information [MFI],Maximum Likelihood Weighted Information [MLWI] Maximum Posterior Weighted Information [MPWI] Maximum Expected Information [MEI] Minimum Expected Posterior Variance [MEPV] Maximum Expected Posterior Weighted Information [MEPWI]) and stopping rules (Standard Error [SE]<0.30, SE<0.50, SE <0.70, Number of Item [NI]=10, NI=20) by calculating the average number of items, standard error averages, correlation coefficients, bias, and RMSE statistics. For all the conditions of the item selection methods, standard error averages, correlation coefficients, bias, and RMSE statistics showed similar results. When the average number of items is considered, MFI and SE<0.30 were found as most appropriate methods to be used in CAT application. For the second purpose of the study, the paper-pencil form of the Vocational Maturity scale and CAT version were administered to 33 students. A moderate, positive, and statistically significant relationship was found between the CAT application scores and the paper-pencil form scores on the vocational maturity scale. As a result, it can be said that the vocational maturity scale can be applied as a computerized adaptive test and can be used in career guidance processes.

The Vocabulary Size Test (VST) is one of the most commonly used assessment tools for measuring English vocabulary size in the field of language testing. Despite its common usage, only a limited number of validity and reliability studies have been carried out with regard to the VST. Besides, they were mostly predicated on the Rasch model. This validation study has attempted to reveal evidence for construct validity for the VST, and to this end, item response theory (IRT) analyses were performed based on the three-parameter logistic model (3PLM). The assumptions of IRT were investigated via factor analysis (unidimensionality) and Yen’s Q3 statistic (local independence). Detailed differential item functioning (DIF) analyses were conducted with Mantel-Haenszel, Lord's chi-square test, and Logistic regression methods to add evidence based on internal structure and to check fairness as a lack of measurement bias. The validation results with IRT showed that the 3PLM fitted the data better than the one- and the two-parameter logistic models. DIF results indicated that 10 items exhibited large DIF (seven favoring males and three favoring females). The results further showed that the guessing effect was not negligible for the VST.

This study aimed to develop a reliable and valid measurement tool to examine teachers' attitudes towards distance education and perceived distance education skills. The data of the study were collected from 2290 K-12 teachers. In the data analysis, reliability was calculated with stratified Cronbach's alpha coefficient, and for construct validity, EFA and CFA were performed. Bartlett and KMO tests were used for the suitability of the data for factor analysis. It was observed that the calculated correlations among the item and the total score for the 25-item trial form were above 0.20. As a result of the EFA, 7 items that loaded more than one factor, or with a factor loading less than 0.45 were excluded from the scale. Promax rotation revealed three factors with an eigenvalue greater than 1.00. The total explained variance of the final form of the scale (18 items) was found as 53.594%. The fit indices calculated in the confirmatory factor analysis (RMSEA = 0.053; CFI = 0.932; TLI = 0.918, SRMR = 0.055) confirmed the three-factor model. The results obtained showed that the model fits the data. The stratified alpha reliability for the whole scale was calculated as .848. The results of the study show that the scale can measure teachers’ perceived skills, challenges they face, and their attitudes towards distance education reliably and validly.

The purpose of this research is to examine measurement invariance of collaborative problem solving skills measured by PISA 2015 Xandar subtest for Singapore, Norway, and Turkey. The research was conducted with 2990 participants’ data obtained from Turkey (1032), Norway (923), and Singapore (1035) on PISA 2015 collaborative problem solving study. In the first part of the study, exploratory factor analysis was performed to obtain the factor structure of the Xandar subtest. Then, the model data fit was checked by confirmatory factor analysis via X2/df (3.127), RMSEA (0.027), CFI (0.987) and TLI (0.979) values. Multi-group confirmatory factor analysis was used in invariance analyses. The findings show that the collaborative problem solving model met only configural invariance across the countries and has not met the metric, scale, and strict invariance stages. The results show that meaningful comparisons cannot be made between the countries, because the factor loadings, variances, error variances, and covariances differ among countries.

This study investigated the variables affecting the science achievement of eighth-grade students by multi-level regression analysis. The variables included in this research were students’ attitudes, confidence level, value, engagement in science, socioeconomic status, school type, school region, and teacher experience. The study group consisted of 1049 students and 41 teachers. In the first research question, differences in students’ science achievement scores among their schools were investigated. According to the results, the students’ achievements differed among their schools. Approximately 16.3% of the differences observed in science achievement were stem from the differences among schools, and 83.6% stem from the differences among students. In the second research question, student characteristics that explain the differences among the science achievements of the schools have been examined. Students’ socioeconomic level, attitude, and confidence level were only variables that have statistically significant relationship with achievement. Socioeconomic and confidence level variables have a positive effect on achievement, but attitude variable has a negative effect on achievement. In the third research question, student and school characteristics that affect science achievement have been examined simultaneously. The school characteristics that have been included in the regression model were teacher experience, region, and school type. It was determined that none of the regression coefficients for the school characteristics variables were statistically significant in the regression model.

An absence of a scale for measuring exposure to the English language, which has a significant effect on English achievement, was detected in the literature. For this reason, in this study, a six-dimensional scale was developed to detect the level of English language exposure and its construct validity was tested. The factor structure of the scale was determined by exploratory factor analysis with the data collected from 784 university students, 726 of whom are undergraduate and 58 of whom are Master’s and Ph.D. students. Confirmation of the factor structure of the scale was carried out with a measurement model specified in a structural equation model. A structural equation modeling study was performed along with 233 students from English preparation classes at a university. In the structural model, the effect of exposure to English on the students’ scores received from writing in English, speaking in English and the total score (grammar, vocabulary, reading and listening scores) was examined. It was found that exposure to English has a significant effect on all of the three variables. Exposure to English explained the variance of the speaking variable most, while that effect is the least for the writing variable.

In this study, the effects of students’ attitude towards English, foreign language anxiety, exposure to English, school type (i.e. state or private), parents’ English proficiency and education level on the students’ English achievement in TEOG exam are investigated. To achieve this goal, a multiple indicators and multiple causes (MIMIC) model has been developed, and tested based on Stephen Krashen’s language acquisition theory and the literature. According to the research results, attitudes towards English, school type, amount of English exposure, parents’ education level and English proficiency have meaningful and positive effects on English proficiency, while language anxiety has a meaningful but negative effect on it. Moreover, it was found that the effects of parents’ education level and English proficiency and the students’ attitudes towards English on English proficiency are mediated by exposure to English. Therefore, Krashen’s second language acquisition theory stating that those who have positive attitudes towards English will seek more comprehensible input and so will be more exposed to English and consequently will acquire English more is validated.