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Feedback Methods Compared — Candidate 1: PDF Annotation

I have never had a good relationship with paper. As a schoolkid, I brought the wrong notebooks to class; as a teacher, I misplaced assignments. When the possibility of electronic submission and feedback arose, I jumped on it enthusiastically. My first attempt at giving feedback online was to have students mail me files which I would comment on and mail back. Because this was the early oughties, students sometimes didn’t know how to send emails, often didn’t know how to attach files, and regularly saved them in wrong format. Even when I managed to get the files I needed, managing hundreds of emails was a pain, so after a few courses, I abandoned the idea.

When mail was king

Nevertheless, it was the first step on my journey from English teacher to learning technologist, and because I’ve been doing both jobs most of the way, online feedback has always been a major concern. I’ve experimented with a number of different methods, and in this and the following articles, I’m going to compare four of them: Moodle’s PDF annotation, Turnitin’s Grademark, feedback files and Google Docs. All of them work well in their own way, but none of them are perfect; it’s a matter of finding the method that suits your personal and institutional needs.

There are two ways to annotate assignments in Moodle: the built in PDF annotation module and the Annotate PDF Advanced plugin. Both need to be enabled from assignment settings. There isn’t a major difference as the latter is a fork of the former, but I would recommend the plugin if you or your users will be doing a lot of PDF annotation; its extra features make it feel more like a “real” PDF editor, and its chained comments give it some of the functionality of a word processor.

Before grading starts, uploaded work is converted to PDF, and this is where we hit the first snag, as not all Moodle servers are set up to do this, and even when they are, not all files convert successfully. You should therefore first make sure you have a suitable PDF converter installed—see Ben Kahn’s article Moodle PDF Conversion Plugins: the Good, the Bad and the Ugly. You should also set assignments to only accept the kind of files that can be converted. Rather than converting as you grade, Moodle runs batch conversions once every 15 minutes, and we experienced a massive system slow-down after a computer science assignment deadline when the converter tried unsuccessfully to convert hundreds of massive zip files to PDF! (To be fair, this can also be a problem with Turnitin, but at least there the problem is on their server, not yours.)

PDF Annotate standard toolbar

Once you have your PDF, you have the normal array of tools, such as highlighting, underlining, comments and stamps. The module comes with just a tick, a cross, a smiley and a frowny preinstalled, but you can upload your own images to create custom stamps (I made a skull and crossbones stamp for really bad errors!).

A particularly useful feature is the quicklist (accessed through the dropdown menu in a comment box), which lets you save comments for future reference.

Comment box with quicklist

Overall, PDF annotation is fairly easy to use and has the major advantage of having everything inside Moodle. It does not have the functionality of a dedicated PDF editor like Adobe Acrobat, and it has a few irritating drawbacks, like not being able to highlight more than one line of text at a time, but it does the job—if your feedback needs are limited to short comments and highlights, this is probably the way to go.



  • Simple to use
  • Everything is inside Moodle
  • Some customisation, especially with PDF Annotate Advanced


  • Server needs setting up carefully
  • Limited set of editing tools
  • Can share stamps but not comment banks (quicklists)

in the next article, we will look at Turnitin’s popular Grademark feature.

Robin Turner
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Robin Turner

Until recently, EAP instructor and Moodle systems administrator at Bilkent University, Ankara, now Learning Technologist at the Global Banking School's London Greenford campus. Interested in educational technology and gamification/game-based learning.

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