What is the basis for saying that the Catholic Church is the largest charitable organization in the world? I would prefer actual numbers comparing it to other organizations.

In addition, bonus points if you can demonstrate that the catholic church effectively does the most good or essentially highly efficient with how they spend their money.  It is quite irrelevant if someone receives lots of donations but does not spend the money well.  None of the links in the following question seemed to work or seemed highly speculative to me (the economist answer).

This question is related.  This is is a source I found online; I'm not sure what to think of it though.
Three factors enter in to answering this question.
Number 1 ). is the Catholic Church a charitable organization?


  A charitable organization is a type of non-profit organization (NPO). It differs from other types of NPOs in that it centers on philanthropic goals as well as social well-being (e.g. charitable, educational, religious, or other activities serving the public interest or common good).


According to that definition yes the Catholic Church is a charitable organization.

Number 2 ) how many people make up the Catholic Church?


  There are an estimated 1.2 billion Roman Catholics in the world, according to Vatican figures. More than 40% of the world's Catholics live in Latin America - but Africa has seen the biggest growth in Catholic congregations in recent years.


That means the charitable organization known as the Catholic Church is 1.2 billion people strong.

Number 3). Is there any other charitable organization that can claim more than 1.2 billion people as members?

No there is not.

Therefore the Catholic Church is in fact the largest charitable organization on earth.