The field data collection error refers to missing data rather than an data analysis based on an incorrect sample or incomplete data. It can be not easy to maintain a high response rate on a large-scale survey. Environmental or observational errors may cause measurement errors. It’s not the same as random errors that have no known cause. Read more @ https://pubrica.com/academy/systematic-review/how-to-handle-discrepancies-while-you-collect-data-for-systemic-review/