Default Date for Birthdate

Question

When the date of birth is asked to the user, with a Date Picker on mobile, what should be the default date to show on Date Picker? Current date makes no sense to me as it is probably too far from the date the user has to select.

EDIT 1. I'm talking about a Date Picker on Mobile. When the users selects the date picker it needs to open in a date and then the user starts moving it. Date pickers do have a default date. I cannot have a Date Picker without default date.

Answer 1

Depending on the target audience of the app, i reckon one could set the default date as the minimum expected age . For eg if the minimum expected age is 18 , show the default date as 01-Jan-1998 in the widget

Answer 2

You shouldn't set a default for a birthday. Just as you shouldn't set a default for:

• Name
• Email
• Credit card number
• Credit card expiry date
• etc.

The line of reasoning goes like this:

Usability

Usability is a measure of performance load, which is broken down to:

• Cognitive load - the effort users expend when perceiving, interpreting and making decisions regarding the next action. Normally meassured in time between exposure to the interface and action onset.
• Performance load - the effort user expend when taking an action. Measured using mouse miles, mouse clicks, keystrokes etc.

So unless some business goals take priority, the a key role of a design (and a system in general) is to minimise performance load.

Social threshold

When making UX decision we sometimes use data or guesstimates as to what percentage of users will benefit from a particular design.

For instance, you may see from analytics that 98% of users has a display size wider than 1200px. So setting your layout width to 1200px may benefit 98% of users, but for the remaining 2% the layout may start stacking, or you can force horizontal scroll - neither is ideal. But all taken into account, it seems a reasonable change to make.

Some set the social threshold to the famous 80/20 rule - if more than 80% of the users will benefit, it's a design worth going ahead with. But, as always, many variables could affect such decisions.

Cost/benefit analysis

Cost/benefit is another commonly employed analysis helping to make design decisions.

If you do set a default date, you will get 'perfect hit' in very roughly 1 in 15000 users (assuming an age span of 40 years). That's around 0.007% of the users.

You may argue that 0.007% is better than 0% (with no default), so lets consider the cost for all the other 99.993% of users:

They may wonder why the field is populated, which could increase the cognitive load a bit. But perhaps the main danger here is security - in the age of cookies, it may appear to some that the form was field previously by another user, it which case some privacy concerns may arise. At any rate, you run the risk of confusing users.

Conclusion

The overall approach to this problem can be depicted like so:

So given the low percentage of those who will benefit from a birthday default, and the potential security and confusing cost nearly all users will experience, this seems like a clear-cut don't provide a default.

Answer 3

I do not think that you should show the minimum age. This will lead to more people just using that that date to log in. If you were to data mine this, the information would not be reliable.

why not just use the --/--/---- format?

Its quick and easy, allows for the users to quickly pick their birthdate. If your target audience is 25-35 years old have the years in the year box start from 1980 to 1994.

Although I will admit, I have just randomly selected dates before. Just to get in.

Answer 4

If you have an age limit for your users, you could auto calculate that from the current date and populate as default.