phpesp-devel

[phpesp-dev] Rank problem when answer not required (revisited)

[Paul B. <pbo...@sc...>]

Dear developers,

Regarding the possible problems with ranking questions and where answers 
are not required, I have a small suggestion.

To distinguish between unanswered questions and rank 1 answers which 
both become 0 when stored in the database and corrupt the results, a 
"magic" number could be set as the default value in the database (say 
-99999).

  => The statistics scripts for previewing the result can easily take 
this into account, as well as statistical packages. It is also backwards 
compatible with respect to existing results.

Any comments?

Regards

Paul

Re: [phpesp-dev] Rank problem when answer not required (revisited)

[James F. <jf...@uv...>]

Quoting Paul Borgermans <pbo...@sc...>:

> Dear developers,
> 
> Regarding the possible problems with ranking questions and where
> answers 
> are not required, I have a small suggestion.
> 
> To distinguish between unanswered questions and rank 1 answers which
> 
> both become 0 when stored in the database and corrupt the results, a
> 
> "magic" number could be set as the default value in the database (say
> 
> -99999).
> 
>   => The statistics scripts for previewing the result can easily take
> 
> this into account, as well as statistical packages. It is also
> backwards 
> compatible with respect to existing results.
> 
> Any comments?
> 
> Regards
> 
> Paul

Paul,

Are you certain that unanswered questions are not NULL?  It's been a
while since I looked at this, but I thought that's what was used for
unanswered questions.  If it is not the case, I believe it should be.  A
 NULL value makes more sense to me than a magic number.

-James

Re: [phpesp-dev] Rank problem when answer not required (revisited)

[Paul B. <pbo...@sc...>]

James,

Thank you for your fast response.

No, unanswered questions are set to 0 because a value *is* required. 
Even when specified a NULL to put there, it becomes 0 because the table 
field properties require it to be NOT NULL. By default this is 0 in 
MySQL. This was originally from a 1.4 installation, but even in the 
1.6.1 archive it is still like that:

-- # answers to rank questions
CREATE TABLE response_rank (
	response_id	INT UNSIGNED NOT NULL,
	question_id	INT UNSIGNED NOT NULL,
	choice_id	INT UNSIGNED NOT NULL,
	rank		INT NOT NULL,
	PRIMARY KEY(response_id,question_id,choice_id)
);


Perhaps it would be nice to have a small additional ENUM field that sets 
wether a value is entered or none to avoid ambuigities (perhaps also for 
future other question types since it may also arise when for example an 
integer 0 would be a valid answer for a question).

Or is there already something like that that I overlooked (and with 
which I could recover the data for a large phd related survey)?

Thanks anyway for your development of phpesp which is still a very good 
package and used by a few collegues.

Regards

Paul

James Flemer wrote:


> 
> Paul,
> 
> Are you certain that unanswered questions are not NULL?  It's been a
> while since I looked at this, but I thought that's what was used for
> unanswered questions.  If it is not the case, I believe it should be.  A
>  NULL value makes more sense to me than a magic number.
> 
> -James