# Statistical Disclosure Control (SDC) Quiz
>Last modified: 16 Jul 2025

<div style="background-color: rgba(0, 178, 169, 0.3); padding: 10px; border-radius: 5px;"><strong>This quiz tests your understanding of UK LLC's Statistical Disclosure Control (SDC) rules.</strong></div style>  
<br>

This quiz acts as a refresher to the Office for National Statistics Accredited Researcher Training that all UK LLC users are required to undertake.

[Click here](../user_guide/SDC.md) full details on the SDC rules UK LLC enforces on all information leaving the UK LLC Trusted Research Environment (TRE).

## 1. What is the UK LLC 'low count' threshold?

<aside class="dropdown admonition tip"><p class="admonition-title">5</p><p>❌ Wrong answer, try again!</p></aside>

<aside class="dropdown admonition tip"><p class="admonition-title">10</p><p>✅ Correct! UK LLC permits file out requests where counts of individuals are >=10.</p></aside>

<aside class="dropdown admonition tip"><p class="admonition-title">20</p><p>❌ Wrong answer, try again!</p></aside>


## 2. Which methods can you use to avoid low counts in output files?

<aside class="dropdown admonition tip"><p class="admonition-title">Put in dummy figures, averaging values, rounding values or suppressing/masking values</p><p>❌ Wrong answer, try again!</p></aside>

<aside class="dropdown admonition tip"><p class="admonition-title">Aggregating/combining categories, delete values, rounding values or suppressing/masking values</p><p>❌ Wrong answer, try again!</p></aside>

<aside class="dropdown admonition tip"><p class="admonition-title">Aggregating/combining categories, averaging values, rounding values or suppressing/masking values</p><p>✅ Correct! These are the suggested methods for dealing with low counts before submitting a 'File-out' of the UK LLC TRE.</p></aside>


## 3. Which accompanying information about the variable 'w1edu' is sufficient?

<aside class="dropdown admonition tip"><p class="admonition-title">Wave 1 participant's Education level (Highest qualification)</p><p>✅ Correct! The supplementary information provided for 'w1edu' clearly describes what the variable measures.</p></aside>

<aside class="dropdown admonition tip"><p class="admonition-title">Self explanatory, most researchers know what this variable means</p><p>❌ Wrong answer, try again!</p></aside>

<aside class="dropdown admonition tip"><p class="admonition-title">W1, Educ of child</p><p>❌ Wrong answer, try again!</p></aside>


## 4. Which symbols can you use to mask low counts?

<aside class="dropdown admonition tip"><p class="admonition-title">0,$,X</p><p>❌ Wrong answer, try again!</p></aside>

<aside class="dropdown admonition tip"><p class="admonition-title">0,NA,NULL</p><p>❌ Wrong answer, try again!</p></aside>

<aside class="dropdown admonition tip"><p class="admonition-title">*,$,#</p><p>✅ Correct! Other common ways include '-', '.' ,'< 10' and 'SUPP'.</p></aside>


## 5. When you suppress values what else do you need to do?

<aside class="dropdown admonition tip"><p class="admonition-title">Include a key outlining which values equate to which masking symbols</p><p>❌ Wrong answer, try again!</p></aside>

<aside class="dropdown admonition tip"><p class="admonition-title">Include a clear note regarding why you chose your masking symbol</p><p>❌ Wrong answer, try again!</p></aside>

<aside class="dropdown admonition tip"><p class="admonition-title">Include a clear note regarding what the masking symbol indicates</p><p>✅ Correct! An example note: ‘-’ indicates suppression due to low counts.</p></aside>