# How long does it take a user to find and click an object in a list?

I tried finding some data/research on how long it takes a typical user to find and click on an object located in a list but didn't stumble upon anything useful. The specific context I am dealing with uses the following scenario:

1. User is waiting for a particular visual event to occur
2. Once the event occurs, the user must find the object in the list...
3. ... and click on it

Based on Wikipedia, the average human reaction time to visual stimulus is approximately 190 milliseconds so the transition from Step 1 to Step 2 should take roughly that amount of time.

There is potentially a Step 1b where the user needs to process new information in order to determine which object is the correct object to find and click but I am not interested in dealing with that complication yet.

This question is focused on the time it takes for Steps 2 and 3 combined.

As a trivial example, here is a JSFiddle output of a list with buttons. Once the event occurs they must find a particular object (say, Kajigger) and click on the appropriate button.

• Just curious why would want to know this information? Oct 21, 2014 at 17:31
• I have been writing a series of articles on the math behind Incremental Games. One of the effects I've noticed is that balancing passive resource income needs to take the user reaction time into account. If you assume they play with perfect reaction time, you can tune the balance incorrectly making the game feel too easy. At least, that's my current theory. But knowing what a typical reaction time actually is will help me determine if my theory is correct or just bogus. :) Oct 21, 2014 at 17:46
• Thats interesting and I would love to read those articles if they are online. That said, you do realize that a perfect reaction time would depend on multiple factors such as the attention span of the user and the relative position of the users mouse with regards to the correct action and so on. Oct 21, 2014 at 17:48
• @MrHen In addition to Fitt's Law mentioned by Mervin, you may also wish to look into the various time constants various GOMS frameworks use. And I'd also look at Hick's Law, which is already linked within the link you have shared. Oct 21, 2014 at 22:46
• You can simulate the actions and get time estimates using CogTool. It is based on ACT-R and some form of GOMS. Oct 22, 2014 at 18:04

I am not sure you are going to find a optimal time it would take for a person to react to a visual stimuli and find content as there are multiple factors here

1. The attention span of the user
2. The relative speed of the user in scanning the content to find the content he is looking for
3. The position of the users mouse or finger or pointing or interaction device with regards to the correct answer. This is in direct co-orelation with Fitts Law

The key statement of Fitts’s Law is that the time required to move a pointing device to a target is a function of the distance to the target and its size. In layman’s terms: the closer and larger a target, the faster it is to click on that target.

Hence if you are planning to conduct a series of tests to determine the total time,you would need to account for the above mentioned conditions while also keeping the fourth one very focussed with regards to the position of the content to be clicked and the position of the user at that point of time.

I recommend reading this excellent research article which should give you some inputs on how to potentially measure this time taking the size of the hit area and the distance into consideration.

• (1) is going to be somewhat impossible to predict but I can use average reaction time (~190ms) as a placeholder. (3) is great info; that answers one of the two pieces. I would be surprised if no one has studied (2) but I feel like there are a great many factors that could speed up the scanning (e.g., graying out invalid click options if possible). But anyway, this gets me one big step closer to what I wanted. +1 Oct 21, 2014 at 19:11
• You are right to say that 2) has a lot of variance. I would be careful in making any assumptions about it. There are so many factors that will affect it - Is the list in the order the user expects? Are the list items worded in a way that's familiar to the user? Do they have any accessibility or mental challenges - e.g. Are they reading the list via a screenreader? Do they have dyslexia? Do they have mobility issues? You may be able to make assumptions based on a particular group of users that are applicable to that type of user, but getting something that's universal will be very difficult. Oct 21, 2014 at 20:21
• There is also Hick's Law, which describes the time it takes for a person to make a decision as a result of the possible choices he or she has: increasing the number of choices will increase the decision time logarithmically. en.wikipedia.org/wiki/Hick's_law Oct 24, 2014 at 8:21