about metis balance factor

8 10 1
2 2 3 3
1 2 4 1 3 8
1 3 2 8 4 8 6 5
2 1 3 8 5 5
4 5
3 5 8 7 7 4
8 3 6 4
7 3 6 7

Metis output is as following?
**********************************************************************
METIS 4.0.1 Copyright 1998, Regents of the University of Minnesota

Graph Information ---------------------------------------------------
Name: test.graph, #Vertices: 8, #Edges: 10, #Parts: 3

Recursive Partitioning... -------------------------------------------
3-way Edge-Cut: 14, Balance: 1.12

Timing Information --------------------------------------------------
I/O: 0.000
Partitioning: 0.000 (PMETIS time)
Total: 0.000
**********************************************************************

My questions is how does Balance compute?
Could somebody give me an example about how to compute balance? I do not see any explaination on document