AQA Large Data Set Practice Test 2026 - Free AQA Practice Questions and Study Guide

Filtering data effectively hinges on handling irregular or problematic data that can cause filters to behave unpredictably. Missing dates or locations create gaps that filters might treat as missing or exclude entirely, which can bias results. Unrealistic values—like negative quantities, impossible dates, or out-of-range numbers—can cause filters to pass records that shouldn’t pass or drop ones that should, skewing conclusions. Inconsistent formatting, such as dates in different formats or location names with typos or varying spellings, makes the same rule apply inconsistently, so some records slip through while others are blocked. Tackling these edge cases through data cleaning and standardizing formats ensures filters behave as intended and results are reliable. Larger dataset size is more about performance than about these data-quality quirks, and having no missing values or using only numeric fields doesn’t introduce the typical edge-case filtering problems.