Having just completed data collection, 4500 surveys, we're cleaning the
dataset and found a funky error.
0.2 % of the time, ODK will write data into the wrong node of the instance.
It is a rare issue, but I thought I should bring it to light. You will only
notice it if you are doing a large enough survey, and carefully scour your
data for errors.
The way we found this error is looking for outliers, an answer in a node
that is unlike all the other answers. For example, it question 99 is a
Yes/No question, then in the instance, the data should look like
Yes or No
This error will manifest by writing the data from the adjacent question into
If the adjacent question, q98, is "What is a lucky number" you may see the
answer '7' written into the node for question 99.
It sticks out because it is an impossible answer for that node.
I find the error in 10 instances out of 4500.
If adjacent questions have similar values, like two scalar questions next to
each other, both with scales of 1-5; this error is invisible.
It seems to self correct within the same record, so that after the error,
nodes and data are re-aligned. I had some fear that it was like buttoning
your shirt, if you miss the bottom button, all the buttons are wrong...but
it isn't like that.
I am not sure if this is a due to running out of memory, it appears to be a
quick stutter in the data-write, it doesn't spoil the whole record, just a
piece of it. I see the error both in MyTouch 32a and 32b, which have
different amounts of internal memory.
Your thoughts on this issue?
From Sajj House restaurant, Monrovia, best pizza in town~