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Sophisticated Skype: What Makes a Good Call?: Page 2 of 2

Continued from Page 1

Beyond MOS

Beyond MOS scores, Skype for Business flags calls suspected to be poor based on five factors. A call qualifies as poor if:

  • PacketLossRate > 10% or
  • DegradationAvg > 1.0 or
  • RoundTrip > 500 or
  • JitterInterArrival > 30 or
  • RatioConcealedSamplesAvg > 7%

To emphasize, exceeding any one of these thresholds sets the poor-quality call flag. Microsoft uses this same poor call definition in the online Call Quality Dashboard (CQD) and the on-premises Call Quality Methodology (CQM) Scorecard tools.

In our research, calls flagged as poor in certain circumstances loosely correlate with user ratings in some circumstances. For instance, 20% of external calls routed over a VPN connection (no split-tunneling) were flagged as poor, compared to 5% of external calls with split-tunneling in use. Correspondingly, users rated calls routed over the VPN on average 0.3 stars (one third of a star) lower.

So What Makes a Good Call?

Based on our research, no single factor ensures users find calls acceptable. Conversely, many factors, some technical and others behavioral, can cause users to give calls poor ratings. These include:

  • Network bandwidth and latency
  • Not using split-tunneling for external calls
  • Processing power of end-user devices -- e.g., users with more powerful laptops, faster CPUs, and more CPU cores generally have higher-rated communication experiences
  • End-user devices (headsets); using an approved headset yielded user ratings minimally above ratings when using built-in laptop microphones or audio devices plugged into the audio jack -- we've been surprised at how minimal of a difference
  • Conference join times -- how long a user waits before being admitted to a conference call; the Monitoring Server Conference Join Time report provides this detail
  • Environmental factors -- approximately 20% of calls rated fewer than three stars by users because of background noise on the call; this is mostly a behavioral issue, although noise cancelling headsets might diminish background noise

More perplexing, the correlation between ratings of users who participated on the same conference call is weak. That is, one user might rate the call quality as five stars (very good), while another user on the same call rates it as three stars (fair). We believe expectations play a strong role in a user's interpretation of Skype for Business call quality. While most users have been trained to accept as normal cellular calls dropping while in an elevator or when driving into an underground parking lot, perhaps the relentless UC industry chant of "any device, anywhere" has inflated expectations for UC calls, even in compromised environments.

Ultimately, a communication experience is good if a user declares it so. As such, analysis of what makes a call good should start with Rate My Call data and then look for positive factors that correlate strongly for highly rated calls (an average user score of 3.5 or higher) or negative factors that correlate strongly with poorly rated calls (an average user score of 2.5 or lower). In some cases, simply talking with users who consistently provide low scores causes their scores to increase. Repeated one-star call ratings might end up being a protest vote against change or a method to seek more attention from IT, and talking directly to your end users is always a good call!

The EnableUC Skype Insights service provides customized analysis and recommendations based on your specific data. Quantified metrics help ensure you're delivering a robust, high-quality, and reliable service that's being well adopted and can drive continuous improvement. If you have specific reporting questions please comment below, send me a tweet @kkieller, or message me on LinkedIn.