Marsh and his colleagues define method effects as "nontrait effects associated with idiosyncratic aspects of particular items or methods of data collection" (Marsh et al. 2013, p. 112).
Decisions about items, scale, method of data collection and presentation of results.
There were missing values on all 20 variables (i.e., nine PHQ-9 items, seven GAD-7 items, age, gender, mode of data collection, and ethnicity); 17.47% of participants had missing values; and 5.01% of values were missing.
Cab rides were undertaken as part of the research work, but there was no report of a suspicious item during this part of data collection.
Data are typically collected via telephone or face-to-face; however, no study has statistically investigated whether the questionnaires' items operate equivalently across these modes of data collection.
Due to the complex nature of treating patients with bladder cancer, the difficult course leading up to the surgery, and the method of retrieval of the survey, several items were missing at the time of data collection.
After the first year of data collection, some items were modified: The response category "with person met online" was introduced into the questions on condom use with different partners, and the response option "I was certain that sex partner was HIV negative, because we talked about our serostatus" was added as possible category to the questions on reasons for not using a condom at last sex.
If applicable, we also appraised four design-specific items: randomization, blinding, clustering effect, and number of data collection points.
A watching brief of policy documents, grey literature, media reports, and other relevant items will be managed throughout the period of data collection.
Whilst the ARQ-Rev1 was relatively long (140 items in total), being over inclusive at this stage of development facilitated selection of the best items and scales in the second phase of data collection and revision described in Study 2. Eleven of 12 secondary schools randomly selected from all Victorian Government schools agreed to participate in the study.
