Filtering & Sorting

It's quite common for users to apply multiple filters in their search for specific content. However, this can sometimes lead to a very narrow set of results. Additionally, users may change their minds and wish to search for something entirely different.

While it's helpful to be able to remove filters one by one, it can be quite laborious and time-intensive to go through and remove each applied filter individually. Providing a feature that allows users to clear all filters with a single click can be a significant time-saver and convenience, especially for those shopping on mobile devices.

Many users confuse the terminology for filtering and sorting options and sometimes use them interchangeably. However, the difference is significant. Filters set hard boundaries so that the page shows items that strictly match the specific selected criteria. Sorting sets soft boundaries. Instead of excluding items, it arranges them in a specific order.

According to the Baymard Institute's studies, users often are more inclined to use sorting. This is because:

• Users are afraid to lose relevant products that fall just outside their defined filter range.
• Users may not know the product's domain or technical characteristics well enough to set the filtering criteria.
• Users may not be so sure about their budgetary limitations, compatibility requirements, usage conditions, etc., and prefer browsing until they find out what they like.^[1]

Ultimately, users need both filtering and sorting functionalities to find relevant content. So make sure you provide both.

Displaying the number of available search results when users apply filters helps them get a clear understanding of how many items match their criteria. In addition to placing this information near the filters, consider incorporating it into the Apply button. 

By doing so, you effectively reduce the interaction cost for users by limiting the steps users take to achieve their desired outcome, such as finding a specific product.^[2] For instance, when the number of items found is too small or even zero, users might not proceed to click the Apply button immediately. They may first remove a few filters in an attempt to broaden their search and potentially see more results. This additional step can be a significant factor in user satisfaction and ultimately lead to more successful searches and purchases.

When it comes to mobile apps, displaying all available filters directly on the screen can potentially obstruct other important content. To prevent this, initially conceal the filters behind a designated Filter button. This button should be strategically positioned above the search results.

Upon clicking the Filter button, users can then access the filter options. This action expands the menu or directs them to a separate page dedicated solely to filter choices. It ensures that filters remain accessible but do not overwhelm or clutter the initial screen, allowing users to focus on the content they're interested in.

When users are on the lookout for specific items, they often apply numerous filters. Horizontal filter panels are a great solution for this purpose.

Unlike the sidebar, horizontal panels are more attention-grabbing. However, it's worth noting that horizontal filtering does have a limitation — space. If your website hosts multiple filters, expanding them horizontally may consume a substantial portion of the screen, necessitating users to scroll to view the results.^[3] 

To mitigate this, prioritize essential filters like price and brand, keeping them visible, while the others can be tucked away. This ensures a balanced approach, offering necessary filtering options without overwhelming the user interface.

Vertical filter panels are a classic and widely recognized filtering tool. Unlike their horizontal counterparts, vertical panels have the advantage of accommodating large numbers of filter groups, making them particularly suitable for desktop devices.

However, it's worth noting that vertical filter panels tend to consume a significant amount of horizontal space. Research from the Baymard Institute indicates that users often overlook them entirely.^[4]

Therefore, the choice of filter panel type should be based on your specific requirements, the space available, and the quantity of filter options you're dealing with.

Showcasing the most popular filter options upfront in UI design not only makes navigation smoother and more intuitive, but it also saves users' time and accurately reflects their needs. To determine which filters are the most popular, designers can:

• Regularly review user interaction data to identify trends and preferences.
• Gather direct feedback through user testing or surveys, gaining valuable insights into the filters users find most useful.

Imagine you're on an e-commerce website looking for a new pair of sneakers. If you're presented with a long, unorganized list of filters, it would be quite challenging to quickly find what you're looking for. You might need to look multiple times to locate the specific parameter you're interested in. This can be frustrating and time-consuming for users.

This is where the concept of grouping filters comes into play. Instead of displaying all the filters in a single, overwhelming list, you can organize them based on common features. For example, in the case of sneakers, you might have filters like size, color, brand, price range, and material.

When searching for specific criteria, like vacation lodging for a large group, there's often a need for multiple selections within a single filter category. For instance, you might require multiple beds, pet-friendly, smoking allowed, wifi, air conditioning, breakfast, and nearby dining options.

Functionally, radio buttons allow only one selection. Unless the options eliminate each other, checkboxes provide a more flexible search. So make sure your filters incorporate checkboxes for categories where multiple options can be selected.

Using appropriate terminology for filter labels is crucial for user comprehension. Labels should reflect familiar, widely used language to ensure clarity and ease of navigation. For example, opt for terms like "Fabric" instead of technical jargon like "Textile."

Engaging with users or conducting research helps identify the terms they commonly use. This practice minimizes confusion, ensuring a seamless browsing experience and aiding users in finding what they seek.

Research tells us that websites should display applied filters twice — by adding a checkmark in the selected option's checkbox and by providing an overview.^[5]

Utilize tags to present applied filters in a clear overview. They summarize the chosen criteria, offering users a quick reference for their selections. This enhances user awareness of their active filters and facilitates easy removal or adjustment, streamlining the browsing experience.

People have diverse ways of processing information. For swift scanning of numerous options, a list view is effective. It allows users to quickly skim through. On the other hand, the grid view offers larger images and concise product information, providing a snapshot before users delve into the product page for detailed information. Offering these various view options grants more flexibility to users.

When designing filter panels, try to minimize the interaction cost for your users. Avoid forcing them to save each filter preference individually or requiring excessive button clicks. Employ intuitive icons and tooltips for clarity, and consider implementing auto-updating of results as filters are applied or removed. Keeping the user experience smooth and friction-free is paramount in enhancing usability and satisfaction among your users.