Review: Crot 2.0 for Moodle 2.0

The plugin for todays review is the Crot 2.0 Free tool for plagiarism detection for Moodle 2.0

For those who don’t know what Crot is, it is a tool which compares assignment submissions to those in the Moodle install and to items on the web using the Bing search engine. This was available for Moodle 1.9 but had to be redeveloped to fit in with the new plagiarsim detection plugin structure in Moodle 2.

This module is maintained by Sergey Butakov, Svetlana Kim although has had others work on it too.

What does it do?

The plugin uses in document fingerprinting technologies for pair-wise document comparison and the Bing search engine to perform global search for text extracts. After the assignment is finally submitted, the cron job of Moodle first queues and then processes the document searching locally (if chosen) and globally on the web (if selected). The results are then displayed to the teacher of the course on the assignment view pages.

Is it simple to install?

Yes. The file is hosted in Moodle Contrib so you can download the zip file from there or browse the source code. The zip holds one folder which contains the files for plagiarism plugin. Once you unzip, you need to upload the crot folder into your Moodle 2.0 plagiarism folder.

You then need to make sure you have the advanced settings for plagiarism plugins enabled as below:


Advanced Settings Options

When upgrading through the notifications page, it installed successfully without any issues.

There was quite a few global settings for the Activity Module which can be seen in the images below, however you also need to have acquired a BING  api ID  to be able to use the service. I wont go into that here, but it is very simple to do.

Crot Settings page 1

Crot Settings page 1

Crot Settings page 2

Crot Settings page 2



As I always do, I left the settings as default except for the Bing API ID. It is always good to check if the default settings work for you, but the options here offer lots of customising to the setup.

Is there documentation for it?

There is no Moodle Docs page for the plugin or a documentation link in the plugin database which is what is preferred however, there are very clear instructions on installation in the README in the zip file. It describes the installation and configuration including how to apply for a BING application ID. I would recommend that it gets a Moodle Docs page at some time.

Is it easy for the teacher/admin to use?

Currently it only works on the advanced uploading one. Setting up the plugin on the assignment is very easy, after that its all about seeing the results.

The first change is that on the view assignments page you get a %  beside the assignment of how it compares to other items  as shown below:

View Assignments with Crot %

Once you click on the %  you get a more complex report showing in-moodle and global similar documents and their % similarity. The image below shows an example report which came from me submitting an extract from a blog entry.

Then when you click on an entry you get the below inline comparison. All very cool.


The red lines are entries which were matched. Not every thing matches, but its still very good report and result.

Is it easy for the learner/student to use?

This is easy to use for students. I have only tested it with a text file, but as long it eventually works fine with word, and pdf it is great.

When the student sees the % and clicks on it  they get a error message saying  “error/The block is under construction.
You have to be a teacher to see its content” which is fine, i look forward to seeing the ultimate student views here.

Does it do what it promises?

Pretty much. This delivers in-moodle and web-wide sanity check on the content for similar texts. For a free tool it is impressive, and a great resource to have available.

I am not doing technical tests, but as this is driven through cron, I do have to wonder how it will effect a server if it has 500 or 1000 assignments to process.

I also wonder if it may be a good idea to take this local search/web concept a stage further by having an  in-institution dedicated server which handles the checking and not have it run on the Moodle site itself to avoid extra load.

Either way, great block even now, will keep an eye on this as its features increase.

Stars: 3 out of 5 stars for this block.


**Standard Reminder**

These reviews check out the plugin for usability not for security. If you are considering installing any module on your site you should also check that is secure and does not impact the server performance.

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