Approaches for linking form instance changes to individuals

second feedback:

"Option 2 looks most promising. In addition to that, for clinical trials I would like to add that:

  • It is absolutely key that there is user verification with password when entering data (whether initial entry or changing data). Otherwise you cannot trust the name that is assigned to the action in the audit trail. The audit trail is used in clinical trials to prove no one had access to the data that should not have had access to the data, that only trained and qualified personnel has entered data, to check if data has been entered according to a logical time frame (done to detect errors and/or fraud).

  • It would be ideal if you can set reason for change as mandatory at a question level when building the CRF. Because if it is optional, you will still need to check if reasons for change are being given, which leads to extra work. "

I could see easily standard responses (aka select one) being/becoming a high priority fairly quickly. Having to type the same change reason in repeatedly gets annoying quickly. That is, @dr_michaelmarks' "...but the WHY".

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I agree with @aurdipas, that user information ideally comes from the credentials used to retrieve the form, and not from a user-entered field (and OpenClinica maintains sessions to add user info automatically).

I'm fine with option 2 as well.

FYI, to share how Reasons For Change (RFC) are done in OpenClinica. First of all there are special views that require RFCs and others that don't have them at all. I believe it's related to the role of the user and the stage of the review process. This is probably easier to do with webforms than with a mobile app. For the views that require this, we automatically add an input field at the bottom of the page for each field the user changes. These fields are separate from the form. The fields have to be filled in before page-flipping or submission is allowed. There is an option to fill in all of the fields together with one reason or add reasons for individual questions.

Could you post example of how these look in an XForm (XML?) definition? Or is this tagging accomplished entirely outside the form definition?

I'm thinking

<bind ... jr:rfc-prompt="what is your favorite color" jr:rfc-required='true()'... /bind>

to trigger popup when filling in form... Or perhaps better in the control definition itself?

The control for a 'comment' (called discrepancy note in OpenClinica) is defined as in the XLSForm/XForm as I posted above (so just the for attribute and an appearance). The RFC functionality is built on top of that discrepancy note question and has no associated XForm syntax (it's defined by the view that the backend UI launches for that user) but it shares the data structure (stringified JSON for OpenClinica) of the discrepancy note and is shown in its history (which the user can view within the form). RFC is always required for them.

Not sure how helpful that all is though, because that was designed long before any audit functionality was added to the spec, and I'm not advocating for it. The only advantage of their approach is that you can query that comment data (e.g. it has different statuses and they have a custom comment-status() XPath function that can inspect the status of that JSON data). This means they can use it inside constraint and required expressions in XPath. E.g. a question can be required only if it doesn't have a comment or a constraint can include the clause that a value can exceed a limit if it has an 'updated' or 'new' comment.

Though the use by OpenClinica may be useful to see how far clinical trial requirements could go (I think it's way beyond what a generic client such as Enketo or ODK Collect should handle, for sure). Hence none of that specialized stuff has made into the core Enketo. We just made the core Enketo very extensible to facilitate such domain-specific customizations.

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As I understand it, the workflow that @dr_michaelmarks and @chrissyhroberts have described is entirely offline and so there is no entity to authenticate against. The idea would be that someone fills out data on their device and then either reviews it and makes edits later or hands it to someone else for review and editing. It's the same as the paper case where initials have to be relied on. This would be a bit better because you could at least know exactly whose device submitted the data.

In an ideal world, I think Enketo could be used for online edits to extend that workflow. I'm imagining it could have a way to use server auth for this feature. For example, when a user is logged in to Central and launches a submission for edit, Central would pass on some kind of client token/hash that would automatically be used as the user identifier for this feature. I'd see that as a future extension on this spec -- something like if the session (virtual secondary instance) has a user identifier, use that.

You mean for all questions, right? My evolving sense of option 2 is that it would be something like a single audit attribute (e.g. odk:track-change-reasons) that lets the client know to prompt for user identifier and change reason every single time a field is changed from a blank value to a non-blank value. The audit log would get two new columns (e.g. editor-id and change-reason) that would get populated. Editing or saving of the form would be blocked until editor identification and change reason were populated.

Basically this.

That would be very convenient and can be client-specific.

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Will there be daycare services at the convening?... :wink:

Well, first time we could use the login information (username), then if someone edit has to enter his/her user before editing. (Of course no authentication, all offline as paper based).
A bit more of restriction can be added validating the user editing against a csv media file with the list of users "authorized" for editing (?).

Yes. And I like your approach :slight_smile:

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Great progress people!

It's all about enhancing electronic data collection by making is verifiable, have an effective audit trails thus credible/authentic data.

@yanokwa, see how to make a signature feature work. In my view, it could be the most tamper-proof.


Just a minor point but we per se don't need an actual "signature" - an alphanumeric identifier would be fine (that's what Redcap records for example) and the file size of saving a JPG, or in the case of an audit trail multiple JPGs each time a change is made, would be problematic on many places we use ODK.

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The second option seems like the best one to me as well but I'm not sure if I understand everything...
We have many comments here but no one approach (most of them come from the option 2)
We should ask for the user id every time a form is started//edited and write it to audit.csv file and that seems fine, but what about those comments... I saw the sample @LN attached

It assumes that a user should also add a comment just when the form is opened and it's a general comment. Does that make sense to ask for such a general comment before editing anything? I think a user might don't know what he is going to change at that point.
If we want to have a general comment for the entire form it should be displayed when the form is being exited.

Asking for a comment, for each edited question (if a question requires it) seems fine but in that case it should ask for a comment, only not user id becasue it doesn't make sense to duplicate it right?

I think we can implement it in two separate pr (two features):
First of all we should add an option to ask for the user id and a generall comment.
Then we can add an option to ask for comments for each separate questions.

Just to add (although we have incentive enough as is) that we are getting fairly serious interest from major players in other serious epidemic diseases to use ODK if we can get the GCP compliance issues sorted - of which this audit trail thing is the key step.

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FYI I think this would be inadequate; I can certainly see any change to a response - eg from "Fail" to "Pass" - as requiring both a timestamp and an optional (or mandatory?) comment. And in the general case potentially a signature too (@dr_michaelmarks?)

I think a fully general-purpose design may well need to fulfill:

  • allow for comment for every change (vs a single comment at beginning/end, or comment only for null-to-nonnull). And we probably want something to flag whether a comment is mandatory or not.
  • timestamp every change
  • allow for 'signature' (or otherwise initial) for every change (vs just a single signature at beginning). And likewise flag if mandatory or not.

Question is, we can we scope it back initially? eg only require signature at beginning (which might determine whether this is 1 PR or more...)

I think we can implement it in two separate pr (two features):
First of all we should add an option to ask for the user id and a generall comment.
Then we can add an option to ask for comments for each separate questions.


@LN and I spent some time iterating on a proposal built around Option 2 and we've published it at

We've put it in a Google Doc so you can easily leave comments. We'd love your comments or objections over the next 5 days. @TSC-1 please also review!

Some thoughts/straw man (google doc comments getting rather long...)

  • when first start up or reopen a saved form, the user has to pseudo-'login' by providing their name/initial in a popup (if odk:track-user set)

  • if odk:track-change-reason (per form or per question?) is set then any user change to an existing non-null value - including initially non-null defaults in the instance XML, or going back and changing a response - brings up mandatory popup to enter reason (this would have to occur after constraint checking). By implication, this change is tagged against the current 'logged in' user, since otherwise Collect has no notion of internal sessions. Note, this (also) occurs when first filling in the form [why? 'cause I dont see a compelling reason to introduce and track a distinct different state to distinguish between before and after saved form state... but perhaps that's open to debate]

  • best practice is that you must 'save' forms before handing the device to another person, who will then have to 'login' using their id/initial should they reopen the form and edit it. Realistically I dont think there's a lot we can do to enforce a re-login when you hand the device to someone else, so it'll just have to be best-practice...

  • any and all changes timestamped, with the initial answering of a question (ie null to non-null) suitably tagged as such, since these wont have a change reason (as described above)

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Thanks so much for all the thoughtful responses, everyone. @yanokwa caught me up on the TSC discussions.

The spec document has been edited to reflect the various feedback received. It's very similar to @Xiphware's strawman above.

You can reach the diff from the last version from File > Version History.

Some things to note:

  • asking for user ID and comments have been fully disaggregated as @Grzesiek2010, @Xiphware and others recommended. They are also completely independent from change tracking. This enables various scenarios such as auditing the identity of users navigating the form without including potentially sensitive form data in the log or using reasons for change as "notes to self" in a one-person data collection context.
  • the ODK XForms spec is deliberately agnostic to what the user identifier is and how it is obtained.

We've gotten feedback on the spec from the research facilitation team at LSHTM and the takeaway is..

The implementation we've specified, paired with appropriate procedures, could be made compliant with good clinical practice (and thus pass internal review boards). LSHTM will put together some procedures about how ODK could be used in a way that achieves all of this, but that shouldn't be a blocker.

All this to say, I think this should settle @TSC-1's concerns. I would request that TSC members (especially @aurdipas, @Xiphware, @martijnr) please review the updated specification at and leave comments. It'd be great to get approval on this in the next two weeks!

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Or slightly less... I'll put it on the agenda for next TSC call to discuss and (hopefully) approve! :slight_smile:


Some additional thoughts after last week's TSC discussion...

One of the issues raised was around when to start tracking these changes; specifically you may not want to have to enter change reasons when initially filling in a form - which will mostly be the "blank to non-blank" scenario. Instead, you mostly want to track changes after initially filling in the form, and passing it off to someone else, or re-visiting it at a later time, or after a 'save' operation [although strictly speaking what constitutes 'saving' a form isnt particularly well defined in the spec...]

But then perhaps some questions are prefilled with defaults, in which case perhaps you do in fact want to track these change in the initial pass? @tomsmyth suggested perhaps we therefore need additional flags to indicate when this feature should kick in: "always", "after-save", or "after-finalize", etc...

My thought was, perhaps for an initial pass of this feature, to perhaps simply if odk:track-changes-reason = “true” then whenever said form is opened - either first time or re-opened - to popup prompt like "Do you wish to track all changes?" and if so have them enter their userid (to be used to tag these changes in the audit log). Although this wont enforce track changes - but instead defers the decision to the user - without a formal 'login'/authorization procedure there isnt a particularly reliable means to determine that a form has actually been passed on to someone else (hence need to start logging their changes) that doesn't effectively rely on the user voluntarily specifying it!

[aside, this would also handle the case when there is no save/validate/finalize step, as in my particular situation]

I'm not strongly opposed to this but I do think it adds undesirable overhead to the user experience. I do feel pretty strongly that if we go this direction, the order should be flipped. That is, the user identifier should always be requested on open no matter what. Then the answer to this question can also be logged and associated with the user who made the decision.

I still think that always tracking changes from non-blank values (including defaults) and never tracking changes from blank values (including values that were set, cleared, then set again), is easy to explain and sufficient but I certainly could be convinced otherwise.

I commented on the doc but it may be easier to respond to different parts of my reasoning here.

Perhaps it would be slightly nicer to have a "pristine state" concept as @ggalmazor alluded to. That way a change from non-pristine blank to non-blank would get a reason for change. But I really do think this situation is rare. The added complexity of keeping a pristine flag for each field seems too high for the benefit it brings.

For non-pristine blank to non-blank to happen, the user would have to blank out a value, navigate away from the field (e.g. by tabbing in Enketo or by swiping in Collect) and then come back to the field to write a new value. This is different from selecting a field with a value in it and changing its value without navigating away (this would be tracked).

The paper equivalent would be crossing out a previously-entered value, doing other things, and then entering a value again. Generally I think that would be given a single explanation. For those who have used such protocols on paper, what do you think?

There is long-press to clear in Collect and the possibility of clearing certain question types by clicking a trash icon in Enketo. In those cases, I think it's reasonable to expect that the reason for change when the value is blanked would be an explanation for why the value is being changed to a new one. I think it would be strange for the user to be prompted again when setting the value.

For those of you who think this is common, could you say more about when it happens?