Read the following:
"Data can be analysed from data that is routinely collected, however specific studies are sometime required to obtain data using surveys, as routine data collection might not be in a usable format, have variations in diagnostic criteria and have gaps or inconsistencies.
Designed studies must be aware of error and bias, including subject variation, observer variation and limitations of the surveying methodologies including sample size, validity and randomness."
Does this best describe pros and cons of:
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