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Safe Exam Browser

Because Rogo doesn’t itself come with a secure browser it prompted us to look for something third-party. A helpful pointer from Farzana Khandia from Loughborough on the very helpful QUESTIONMARK@JISCMAIL.AC.UK list, led us to Safe Exam Browser (SEB). This is a fantastic bit of free software which has a number of advantages over QuestionMark Secure (QMS), including:

  1. Once installed by an administrator, SEB uses a Windows service to prevent access to the Task Manager, Alt-Tab, etc. This means a typical computing lab ‘user’ will be able to run it with no further work. In contrast, QMS requires that typical user to be given read/write permissions on a number of registry keys – a fiddly process and one which upsets many IT officers.
  2. SEB is launched from a desktop shortcut and then calls the assessment server (or other system specified in an ini file before installation). It then carries on running until an IT officer closes it down. QMS starts and stops when a secure assessment is opened and submitted respectively. This leaves the machine unsecured once a participant has submitted.
  3. SEB allows administrators to allow access to ‘Permitted Applications’  such as  the system calculator and Notepad – this is not possible in the version of QMS that we are using.

The only disadvantages over QMS that we have discovered so far are:

  1. The requirement to enter a key sequence to close down the SEB slightly increases the time required to reset computers between sittings of students.
  2. If the machine crashes or is switched off while SEB is running, a bat file needs to be run to re-enable the functions disabled by SEB i.e it only re-enables them itself when it is closed normally.

We’re now considering whether we could use SEB instead of QMS, even with Perception-delivered assessments as it would save us the extra annual subscription for support on that proportion of our licence.

 

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The importance of paper type in Rogo

One of the problems which very nearly forced us to abandon our first test of Rogo yesterday was our lack of understanding of the importance of paper ‘type’ in assessment delivery in Rogo and, arguably, the degree to which we are used to the way that QuestionMark Perception does things.

Test Type Feedback? Restart? Fire Exit? Multiple Attempts? Review Previous attempts?
Self-Assessment Test Yes, granular control No No Yes Yes
(Quiz) (Yes) (Yes if SAYG) (n/a) (Yes) (Yes if enabled)
Progress Test No – but options shown in Assessment properties screen. Yes No No No
(Test) (User decides) (Yes if SAYG) (n/a) (Yes) (Yes if enabled)
Summative No Yes Yes No No
(Exam) (No) (Yes if SAYG) (n/a) (Yes) (Yes if enabled)

The three main assessment types in Rogo (with a comparison with Perception in brackets)

In Questionmark Perception, ‘Assessment Type’ is a convenience method for setting various parameters of assessment delivery. However, the parameters are set explicitly and are visible to administrators. They are also all individually configurable regardless of assessment type.  In Rogo, paper type is considerably more important as, although it sets very similar parameters to those in Perception, they do not seem then to be independently configurable or, crucially, to be visible to administrators. As a result it is very easy to inadvertently, but radically, change the way in which an assessment is delivered. Or as we found, it was not possible to deliver the assessment in the way required at all.

We wanted to be able to deliver a formative paper under exam conditions which would display marks and feedback to students at the end but which would also allow students to restart their assessment if something went wrong before they had finished. We began by setting paper type to ‘Progress Test’ as this gave us the feedback we required but then realised this wouldn’t allow students to restart in the event of a hardware failure. So we tried ‘Summative’ but, despite having ticked the two feedback tick boxes, no feedback appeared. Luckily, since we were only testing the system, we could nip in and alter the offending bit of code (paper/finish.php, line 234) to allow feedback with a summative paper:

$show_feedback = true;

but this wouldn’t be acceptable on a production system.

It seems to me that, in this respect, the QuestionMark Perception model is better – paper type should help by suggesting appropriate settings not by constraining how an assessment can be delivered.

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Hurray – Rogo performed brilliantly in its first real test at Oxford

Monday 23rd April saw a total of 73 first year medics, half of each of two sittings, take their voluntary assessment in Organisation of the Body on Rogo while the other half of each sitting used QuestionMark Perception as normal.

After a longer than usual introduction (see below), to explain the differences between this and ‘normal’ online assessments, we started the group in two halves, approximately 10s apart. There was no perceptible delay despite the fact that both application and db are running on one >3yr old server.

This was a great outcome given that we very nearly abandoned this test of Rogo at the last minute because of serious potential problems – one to do with server errors after amending ‘locked’ questions, the other to do with paper ‘types’. Disaster was averted by my colleague Jon Mason, who spotted and corrected both problems just in time.

Extra instructions at the beginning of the assessment:

“You are in the very privileged position today to be the first group of students to try out a new assessment system, Rogo. This works in more or less the same way as the ‘normal’ system, Perception, except that:
1. The assessment will not submit itself at the end, we will ask you to click ‘Finish’ after 45 minutes;
2. Because it doesn’t time itself, I will tell you when there are 5 minutes remaining to you. There is a clock at the bottom left of your screen – I suggest you make a note of your start time as you would with a normal exam.
3. The questions will be presented on 6 ‘screens’ which you can move between (backwards and forwards) using the controls at the bottom right.
4. When you go back to a screen you have previously visited, unanswered questions will be highlighted in pink.
5. Please make sure you do not click the ‘Finish’ button until you have answered all questions as you will not then be able to return to them.
6. We have appended three questions to the end of the assessment which ask for your thoughts on this new software. You do not have to answer these but we would be grateful for any feedback you can give us – it will help us to decide whether this is a viable alternative to the existing system.”

 

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Question Analysis – Difficulty/Facility and Discrimination

Difficulty/Facility

This is simply a measure of the proportion of students that answered a question correctly and has a value of between 0 and 1. It is calculated by taking the sum of the actual marks for each candidate and dividing it by (the maximum multiplied by the number of candidates).

It is often referred to as difficulty, but should probably be known as facility, as a value of 0 means that no-one answered the question correctly, and a value of 1 means that everyone answered the question correctly.

General wisdom seems to be that questions with facility values of around the pass mark for the assessment (e.g. pass mark = 70%, facility = 0.7) will give the most most useful information about the candidates.

Discrimination

The purpose of item discrimination is to identify whether good students perform better, worse or the same as poor students on a question. Based on Kelley (1939), good and poor students are defined by taking the top and bottom 27% based on overall assessment mark.

Discrimination for a particular answer option is then calculated by subtracting the fraction of the bottom group who gave the answer from the fraction of the top group who gave the answer. So:

  • A positive item discrimination means a higher proportion of people in the top group chose the answer than in the bottom group. A high positive value for the correct answer generally means the question is a good discriminator, which is what we want (but is very difficult to achieve!). A positive discrimination for an incorrect answer may suggest an issue, but could equally just mean that it is a good distractor.
  • An item discrimination of 0 means the same number of people from each group gave the answer, so the answer doesn’t discriminate at all. Questions where everyone got the correct answer will always have a discrimination of 0.
  • A negative item discrimination means a higher proportion of people in the bottom group chose the answer. This would be expected for an incorrect answer. A negative discrimination on a correct answer may indicate something is wrong, as more able students are choosing an incorrect answer.

To make a question a good discriminator, the correct answer should have a high positive discrimination, and the incorrect answers should have a negative discrimination.

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Reporting in Rogo

Currently, reporting in Rogo is only assessment-based. The following reports are available:

  • Class Totals (available as HTML, CSV or Excel) – scores for individuals
  • Frequency & Discrimination (U-L) Analysis (HTML only) – item analysis with frequencies, item difficulty and discrimination value
  • Export responses as CSV file – question by question responses
  • Export marks as CSV file – question by question marks

Class Totals

Example of Class Totals output
Example of Class Totals output (click to view full size)

The class totals output, which is available as HTML, CSV of Excel formats, shows individual results for students who have taken the paper. The table of results has the following headers:

  • Name
  • Student ID
  • Course
  • Mark
  • Percentage
  • Classification (Pass, Fail etc)
  • Start Time
  • Duration
  • IP Address
  • Room
  • Extra

It also produces a histogram for the percentage marks, and a scatter plot of percentage against duration (time taken). Summary statistics, including measures of central tendency, standard deviation and percentiles are also produced.

Frequency & Discrimination (U-L) Analysis

Example of Item Analysis Output
Example of Item Analysis Output (click to view full size)

This analysis is produced on an item by item basis, and is only available in HTML format. It shows the percentage of total respondents who chose each option, as well as the percentage of respondents from the top and bottom groups (the top and bottom 27%, based on overall assessment mark) who chose the correct option.

The p-value, or ‘difficulty’ (actually facility, as 0 = no-one answered the item correctly and 1 = everyone answered the item correctly), is shown, as is the discrimination, d. See the Question Analysis – Difficulty/Facility and Discrimination post for more on this.

At the moment it is not possible to obtain aggregated statistics about a question that has been used in multiple exams. However, the Rogo team have said that this is something that they are looking at for the future.

Export responses/marks as CSV file

The responses export provides a CSV (comma-separated values) file showing the response that each candidate gave,  as a number that corresponds to the option numbers in the question editor (for EMQs/MCQs). It also gives the correct answer for each question/item.

The marks export does the same, but giving the candidate’s mark for each question/item.

Other Reports

It is also possible to output a “Learning Objective Analysis” report, but we have not looked into this yet, as we have not mapped any assessments/questions to learning objectives.

There are also reports available called “Internal Peer Review” and “External Examiners”, but these, I presume, relate to comments/analysis produced during the process of creating the assessment, rather than to student results/question performance.

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CSS – Start values in ordered list

When trying to specify the start value for an ordered list, i.e. to make it start from 4 rather 0, I found that the “start” attribute, e.g. <ol start=4>, had been deprecated in HTML 4 and that it should be done using CSS. However, the CSS is more complicated than it seems it should be for what is a relatively straightforward task. It also seems strange that it should be part of CSS, as the start value is not really a style consideration.

Thankfully, in the HTML5 specification – http://www.w3.org/TR/2008/WD-html5-20080122/#the-ol – the start attribute is no longer deprecated. The same is true of the value attribute for li elements, allowing you to specify the value for a specific list item. So to start a list at 4 and miss out 6 & 7, you would use:

<ol start="4">
   <li>Item 4</li>
   <li>Item 5</li>
   <li value="8">Item 8</li>
   <li>Item 9</li>
</ol>

This gives:

  1. Item 4
  2. Item 5
  3. Item 8
  4. Item 9
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The final ‘ō’ in Rogō

The final ‘ō’ in Rogō is an ‘o’ with a macron, which has numerical code 333 (&#333; for HTML) and HEX code 014D. This seems to cause some problems, as not all text editors are able to read/save the character, e.g. WinSCP’s internal editor, or are not, by default, set up with the correct encoding to read/save it, e.g. Eclipse. As a result, having edited files, we were finding that the titles of pages, for example, contained the ‘Å’ character instead.

We feel that it is perhaps unnecessary to use this special character, and it might be easier to just use a standard ‘o’ instead. However, in order to ensure the ‘ō’ is retained, it was necessary to take the following steps in the editors we use:

  • Eclipse (which gives a warning when trying to save a file that contains characters in cannot encode) – go to Window > Preferences > General >  Workspace and in the “Text file encoding” section, change the setting from the Default (Cp1252) to UTF-8.
  • WinSCP – rather than changing the encoding settings of the internal editor (which doesn’t seem to be possible), I changed the editor that is used to Notepad++, which has many other advantages over the internal editor.

However, there was still a problem with any ‘ō’ contained within the database, e.g. the contents of the help files. Initially, the database would not let me store the ‘ō’ character. This was fixed by changing the Collation from latin_swedish_ci (which it must have defaulted to) to utf8_unicode_ci. The ‘ō’ character can then be saved in the database, but the browsers I have tested it on (IE9, Firefox, Chrome) display the ‘ō’ as a question mark (only for ‘ō’s read from the database though, not ‘static’ ones in HTML files). The only way to get this to render properly in the pages is to replace the character with the html code &#333; or &#x14D;. Therefore, we could go through the SQL files for the help pages (in the install folder) and do a find/replace on all of the ‘ō’ characters, then replace the contents of the help tables.

However, this all seems a bit unnecessary just to get ‘ō’ rather than ‘o’, so we have suggested the on the Rogo mail list that we could drop the ‘ō’ when using it in text, and just use ‘o’.

 

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A minor change to the assessment delivery page

For EMQs in Perception, we ‘manually’ (using our Question Maker) number the question stems with Roman numerals – (i), (ii) etc – and letter the answer options – A, B, C etc. However, in Rogo, the stems are automatically lettered by default. Therefore, having imported questions from Perception into Rogo, the stems had both letters and Roman numerals, e.g. A. (i) The first stem.

To fix this, the options were to change all of our questions when we imported them, or to remove the automatic stem lettering in Rogo. The former would be a prohibitively large amount of work, so thankfully the latter is merely a case of changing one CSS property in the paper/start.php file, line 370. The “list-style-type:upper-alpha” property of “.extmatch li” was changed to “list-style-type:none” to remove the item-marker. There are many possible values for this property – see http://www.w3.org/TR/CSS21/generate.html#list-style.

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Thoughts on Rogo Delivery

The Rogo delivery system seems to be robust and, unlike the admin interface, free from bugs. It also seems fast, and initial load-testing has shown it to be capable of putting up with a reasonable number of students starting or finishing an assessment at the same time, although we have not tested this in a live environment. This is despite us running the system on a single, reasonably-spec’d, but not especially new, server.

One handy feature in the Rogo delivery system, that Perception does not have, is the Fire Alarm button – see https://learntech.medsci.ox.ac.uk/wordpress-blog/?p=15.

However, there are a number of things that are missing, compared with Perception: Auto-save, timed assessments, secure browser.

Auto-save

Rogo is not able to auto-save assessments, e.g. every 5 minutes. It does save when a user moves to another screen (and when the fire alarm button is clicked) but since we prefer to run our exams as a single, scrollable screen containing all of the questions, this is not particularly helpful. However, since the functions are there for saving the current status of an exam while the exam is continuing, it would proably not be a big step to write an AJAX-based auto-save function.

Timed Assessments

Assessments in Rogo are never timed and so do not autosubmit when the time is up. The assessments we have run in Perception have traditionally been timed, so that each user’s time only begins when they enter the assessment page, and the assessment automatically submits when their time runs out. There is also a timer on the page, so the student can see exactly how much time they have left, as this would not be the same for all students. However, we have recently been leaning increasingly towards running untimed assessments, mainly due to the problems of disaster recovery with a timed assessment. For example, if a fire alarm were to go off, it would not be possible to pause the timer and allow students to carry on from where they left off. Therefore, the lack of timed assessments is unlikely to be a major issue, as we were heading in this direction anyway. Nonetheless, it would be good to have the option!

Secure Browser

Unlike Perception, Rogo does not have built in secure browser support. However, there are free secure browsers out there that can be used instead, e.g. Safe Exam Browser – http://safeexambrowser.org. We might cover this more fully at a later date when we’ve done more testing with it. Update: Now covered in this post

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Importing Multiple Users in Rogo

Rogo enables the import of multiple users from a CSV file.

The are a number of required fields, although the order of the fields is flexible. The import does not worry about the case of the field headings, and can accept alternatives for each, as shown below:

  • Student ID: student_id, id
  • Forename(s): first names, forenames
  • Surname: surname, family name
  • Title: title
  • Course Code: course code, course
  • Year of Study: year of study, year of course (1, 2, 3 etc, not actual year, which is held in session)
  • Email Address: email, local email

It is also possible to specify a username for each student. If no username is given, the system will take everything before the @ in the email as the student’s username. A Module and Session (e.g. 2011/12) can also be specified – both are needed for this to be added. Module needs to be the module ID, e.g. OrgBod.

The Student ID does not refer to the student’s username or their database ID (an incremental digit), but a student ID held in a separate table in the database, which does not have to be unique.

Importing a user with the same username as a user that is already in the database will result in that user being overwritten.

There is no way of specifying a password for a user. All passwords are generated randomly and then hashed. This means there is also no way of finding out a user’s password. The only way to define a password for a user is to click “Reset” from the User File, which sends the user an email that they can then click on to set their password. This makes sense from a security point of view, but it is important for us to be able to see user’s passwords (something that is possible in Perception), so that we can log them in if they have forgotten their password, and can test multiple users with defined passwords.

In order to enable defining of passwords in user import, the following was added to import_users.inc:

Line 117:

    //JHM 2012-04-13: Enable passwords to be imported by csv
if (isset($header['password']) && $fields[$header['password']] != "") {	//Check that we have a password header, and the password is not blank for this user
    $password = $fields[$header['password']];
} else {
    $password = PasswordUtils::gen_password();	//No password was provided, so generate a random one
}

Line 137, comment out:

//$password = PasswordUtils::gen_password();	//JHM 2012-04-13: Password now obtained from csv or generated above (line 118)

From looking in the database, this was changing the value of the password for a user, but still did not allow the user to login using the given password. It emerged that this was because the passwords were being doubly encrypted, first in import_users.inc and then in UserUtils::createUser (userutils.class.php line 50). Therefore, I changed lines 137-139 of import_users.inc to:

//$password = PasswordUtils::gen_password();	//JHM 2012-04-13: Password now obtained from csv or generated above (line 118)
//$encpw_password = PasswordUtils::encpw($username, $password);	//JHM 2012-04-13: Password encrypted in createUser below
$encpw_password = $password;	//JHM 2012-04-13: Password encrypted in createUser below, so use plain password

This then worked fine for new user imports, but not for importing users over the top of old users. This required changes to lines 153 onwards in import_users.inc:

$encpw_password = PasswordUtils::encpw($username, $password);	//JHM 2012-04-13: Encrypt password for updating

//JHM 2012-04-13: Added password - 'ssssss' refers to var types, so add extra s to get it to work
$result = $mysqli->prepare("UPDATE users SET yearofstudy=?, title=?, first_names=?, surname=?, grade=?, password=? WHERE username=?");
$result->bind_param('sssssss', $year, $title, $forname, $surname, $course, $encpw_password, $username);

This now seems to work. This issue has been submitted to the Trac system – ticket #701, https://suivarro.nottingham.ac.uk/trac/rogo/ticket/701

We have also made a request for the import to flag up potential problems with header names, and/or enabling users to tell Rogo which headers it should expect, so it can report back if it failed to find any of these. Trac ticket #700 – https://suivarro.nottingham.ac.uk/trac/rogo/ticket/700