- Containers
- Copacking
- Cross-docking
- Drop shipping
- Decision-driven optimization
- DDMRP
- Economic Drivers
- Initiative (Quantitative SCM)
- Kanban
- Lean SCM
- Manifesto (Quantitative SCM)
- Micro fulfilment
- Product life-cycle
- Resilience
- Sales and Operation Planning (S&OP)
- Supply Chain Management (SCM)
- Supply Chain Scientist
- Test of Performance

- Backorders
- Bill of Materials (BOM)
- Economic order quantity (EOQ)
- Fill Rate
- Inventory accuracy
- Inventory control
- Inventory costs (carrying costs)
- Inventory Turnover (Inventory Turns)
- Lead demand
- Lead time
- Min/Max inventory method
- Minimum Order Quantity (MOQ)
- Phantom inventory
- Prioritized ordering
- Reorder point
- Replenishment
- Service level
- Service level (optimization)
- Stock-Keeping Unit (SKU)
- Stockout

This guide explains

When opening the spreadsheet, Excel will warn you than

- The average call duration noted
*t*is known.*t*is located on**B7**. - The number of agents, noted
*m*is known.*m*is located on**B8**. - The call arrival rate, noted λ is known. The arrival rate is the number of incoming calls per second. In the spreadsheet, λ is located on
**B9**.

In the following, based on those 3 variables, plus a couple of statistical assumptions, we will be able to compute

- the average agent occupancy.
- the probability that a call has to wait.
- the probability that a call waits for more than a specified time.

The most important statistical assumption is that the incoming calls behave statistically like a Poisson process. Without entering too much into the details, this assumption is reasonable if the call events are

The

The

The

The

`ErlangC`

macro function implemented in Visual Basic. The `ErlangC`

function takes two arguments, first The

`ASA`

macro function implemented in Visual Basic. The `ASA`

function takes 3 arguments, first The

`ErlangCsrv`

which takes 4 arguments: first In this section we propose to use a much more compact layout illustrated in the screenshot below.

Within the sample spreadsheet, the upper-left corner of illustration here above is the cell

A couple of remarks

- we assume constant average call duration
*t*and constant target time*tt*. - we use static Excel cell reference, i.e.
**$A$1**instead of**A1**for the variables (which facilitate cut-and-pasting the formulas). - agent counts can be freely optimized to adjust the expected service levels.
- cell format properties are adjusted to avoid displaying to many decimals.

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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.