The difference in detection for different milk types is smaller than the difference in test capability by the use of different batches of reagents.
Other factors contributing to the difference in test performance among the studies are related to the use of different experimental protocols and criteria of scoring.
There was no difference in test scores between groups.
When the first test results came back, the vouchers made no difference in test scores for the 2,600 students as a whole.
After taking demographics into account, attendance accounted for 14percentt of the difference in test scores, while teacher certification explained 4.4percentt of the variation in reading scores and 5.4percentt of the variation in math scores.
A significant relationship was also found between the students' positive perceptions about C-R activities and the difference in test performances.
"It seems most likely that the latest test was an attempt to test the Musudan from an operational launch facility rather than a test facility," he said, explaining the difference in test location.
In the 1980s, on an 800-point SAT-type test scale, the average difference in test scores between two such children would have been about 90 points; today it is 125 points.
While the analysis fully acknowledges that there is little, if any, difference in test scores between those who go to preschool and those who don't, it also found that there are "long-term effects on important societal outcomes such as years of education completed, earnings and reduced crime and teen pregnancy".
The novelty factor could explain some of the difference in test scores.
There was no difference in test positivity between clinician-collection, 36.7%, and tampon-collection, 43.5% (p-value = 0.08).
