bfb86586_Test___Test_Your_ISP_Bandwidth__Why_It_Matters
[What's Measured] Packet Loss [What Is It?] Occurs when data units, or packets, fail to reach their destination. [How It's Measured] Measured as a percentage of the total data packets attempted. [Why It Matters] 
Packet loss can severely impact voice call quality by making calls sound choppy. In data usage, buffering and delays will be noticed as packets need to be resent.