Hi, I had an issue with requesting results by batch from MTurk using GetAssignments. The symptom is as follows when I request results for batch 123456, which exists:

  > d <- GetAssignment(annotation="BatchId:123456;")
  Error in GetAssignment(annotation = "BatchId:123456;") : 
    No HITs found for HITType`

The issue is that there is extra information in the annotations field, and GetAssignment() by annotation requires an exact match. After examining the HITs with SearchHITs I find that there is information about OriginalHitTemplateId in the annotations field. After updating the query to add that, the GetAssignment() request works:

  > d <- GetAssignment(annotation="BatchId:123456;OriginalHitTemplateId:9988776655;")
  60 of 60 Assignments Retrieved

I wrote a function, GetAssignmentsByBatch(), that also works for my case:

GetAssignmentsByBatch <- function(batch.id)
{
    stopifnot(is.character(batch.id) && length(batch.id)==1)
    
    result.SearchHITs <- SearchHITs(verbose = FALSE, return.qual.dataframe = FALSE)
    unique.annotations <- unique(result.SearchHITs$HITs$RequesterAnnotation)
    annotation <- grep(paste0("BatchId:",batch.id), unique.annotations, value=TRUE)
    if (length(annotation)<1)
    {
        stop(paste0("Batch ", batch.id, " not found in search results"))
    }
    stopifnot(is.character(annotation) && length(annotation)==1)
    result <- GetAssignment(annotation=annotation)
    return(result)
}

Using this function, I get the results that I expected:

 > d = GetAssignmentsByBatch("123456")
 60 of 60 Assignments Retrieved

If it had been possible to search by wildcard (or, perhaps the best solution would be if GetAssignment() used a contains by default, rather than an exact match, to select the assignments to return), this would have worked. I file this as an issue because I found nothing in the documentation to suggest there was a better way that I should have used.