What is the default installlevel for windows installer?

Question

If you do not provide any installlevel argument to msiexec, what is the default value that the Windows Installer Framework assumes? My tests seem to indicate 1, but I can't find any documentation that corroborates this.

Answer 1

If no value is specified, the install level defaults to 1.

http://msdn.microsoft.com/en-us/library/aa369536(VS.85).aspx