What does "Are Right, A Lot" means?

Question

Amazon has published their Leadership Principles.

There are about a dozen in the list; I will show three of them:

Customer Obsession
Leaders start with the customer and work backwards. They work vigorously to earn and keep customer trust. Although leaders pay attention to competitors, they obsess over customers.

Ownership
Leaders are owners. They think long term and don’t sacrifice long-term value for short-term results. They act on behalf of the entire company, beyond just their own team. They never say “that’s not my job".

Are Right, A Lot
Leaders are right a lot. They have strong judgment and good instincts. They seek diverse perspectives and work to disconfirm their beliefs.

What does the statement "Are Right, A Lot" really mean? Can one say:

"John is right a lot with his suppose about [something]."

Answer 1

"a lot" here is used adverbially. It can mean to a great extent or frequently.

lot
adverb (preceded by a)
13. to a considerable extent, degree, or amount; very much: to delay a lot.
14. a great deal of the time or often: to sing madrigals a lot.
Collins English Dictionary

1.a lot or lots (Informal)
b. Used adverbially to mean "to a great degree or extent" or "frequently": felt a lot better; ran lots faster; doesn't go out a whole lot; has seen her lots lately.
American Heritage Dictionary

That Amazon page lists statements that supposedly apply to leaders.

One of them is:

Are Right, A Lot
Leaders are right a lot.

What they are saying is:

leaders are very often right

In an informal way.

To answer your question

Can one say "John is right a lot..."?

You can, for example:

John is right a lot in his decisions.

But this sounds terrible as a sentence in my opinion.

A better way to say something like this might be:

John very often makes the right decisions.

They've just chosen a quite informal way of saying leaders are very often right.

The word "lot" has many different functions and forms. Usually "a lot" and "lots" act as adverbs, while "a lot of" and "lots of" act as quantifiers, a type of determiner, that is, they tell you a quantity, much like "many", "few", "some" etc.

There are some good sources on the internet about the use of these variants.

Answer 2

To be right=to be correct or accurate

a lot = a lot of time, often, most of the time

As a title: [some people are] Right, A Lot

In your text,it refers to leaders, who are said to be accurate most of the time.

Yes: John is right a lot [in his opinions about x].

You can be right a lot, or conversely, you can be wrong a lot.

Please note: to be right a lot is more of a spoken form. Had I been writing that book or article, I would have used:

Being Right Much of the Time or Being Right: Much of the Time or Much of the Time: Being Right.

Those authors may have written on leadership principles but they are not good writers, in my opinion.

[I have never known a leader to work to disconfirm a belief. That is not even really a word. Good writers would say: challenge their own beliefs.].