# data[].attributes.headline
To allow you to consider all possible variables before data collection

# data[].attributes.subject
To allow you to consider all possible variables before data collection

# data[].attributes.headline
if you have others helping then they can follow your design and allow for smoother data collection

# data[].attributes.subject
if you have others helping then they can follow your design and allow for smoother data collection

# data[].attributes.headline
To design it to be suitable for your project recording expectations. 

# data[].attributes.subject
To design it to be suitable for your project recording expectations. 

# data[].attributes.headline
So it looks like you know what you are doing

# data[].attributes.subject
So it looks like you know what you are doing

# data[].attributes.body
To avoid bias in

# data[].attributes.headline
To ensure you are following a procedure during your experiment, thus reducing the probability of errors in results.

# data[].attributes.subject
To ensure you are following a procedure during your experiment, thus reducing the probability of errors in results.

# data[].attributes.headline
Increase likelihood of success before commencing data collection

# data[].attributes.subject
Increase likelihood of success before commencing data collection