Analyzing Detection, Delay and Response

Instead of using a “trial and error” approach to determine the impact of changes in detection probabilities, delay, or response time, try using the buttons on the top of the EASI worksheet.

Figure 8: Analytical Buttons

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scenario. If you click on the “draw timeline” button you will be taken to another worksheet. But before you may use that worksheet, you have to respond to an Excel query that tells you that the selected sheet will be permanently deleted, and asks your permission to proceed.

Figure 8: Excel Query to Create Timeline

Click on “OK.” All you are doing is erasing the old timeline so that the new on may be drawn.

After you click on “OK” a new timely will be drawn. It provides a graphic view of the timeline of activities associated with your current scenario.

TIP: If you want to save a timeline, click on the far upper right corner of the worksheet. This will select everything on the sheet. Then click on “Edit” and then “Copy.” Click on “Insert” and then “Worksheet” and you will be taken to a new blank worksheet. Click on “Edit” and then “Paste” and the timeline will be copied to the new sheet. If you click on the tab at the bottom you will be able to assign a new name to the sheet. This will save a picture of the timeline with the rest of your EASI file.

Analyzing Response

If you click on the “Analyze Response” button it will take you to another worksheet, such as the one shown in Figure 9.

The figures in the column labeled “Response Time” represent hypothetical changes in response time. In the next column the corresponding PI value for each response time. For

example, if response time is changed to 68, the PI would be 0.606675995.

The graph shows this relationship between PI and response time.

Using this information, you may be able to set a new target for response time that provides the most payoff in terms of stopping inmates effectively.

Time 10 0.765209862 39 0.717203547 68 0.606675995 97 0.548871413 126 0.507606661 155 0.472696643 184 0.441396418 213 0.406832948 242 0.364369734 271 0.315356922 300 0.264745857

Analyzing Probability of Detection

Before you use the “Analyze Detection” button you have to select a cell to be analyzed but clicking on it. If you click on the first PD value in the table, and then on the button,

you will get a new worksheet with values and a chart. If you forget to select a value, Excel will remind you with a prompt.

Figure 10: Analyzing Detection

PD Pi 0 0.175555608 0.1 0.220150732 0.2 0.264745857 0.3 0.309340981 0.4 0.353936106 0.5 0.39853123 0.6 0.443126355 0.7 0.487721479 0.8 0.532316604 0.9 0.576911729 1 0.621506853

The table will tell you the impact of changes in PD on the probability of interruption, and

the graph shows the relationship. For example, if you increase PD to 0.5 the probability

of interruption will increase to 0.443. You may reverse the process and select a

probability of interruption that is acceptable and find the corresponding PD necessary to

achieve your goal.

by clicking on a cell in the delay column, and then click on the button. Figure 11: Analyzing Delay

DELAY Pi 120 0.264745857 128 0.264745857 136 0.264745857 144 0.264745857 152 0.264745857 160 0.264745857 168 0.264745857 176 0.264745857 184 0.264745857 192 0.264745857 200 0.264745857

As with detection and response time, you may use the table and the graph to analyze changes in delay. But in this example, changing delay does not make a difference! This is also good information because it helps you to focus on PPS elements that will have the greatest impact.

8. Using the “Lookup” Function for Delay Values

“Lookup” is another tool that is embedded in the EASI program allows you find how long certain PPS elements delay an action.

The data contained in the lookup function was developed by Sandia National

Laboratories several years ago. This information should be used as a last resort only, for several reasons:

• It was not initially developed for applications in corrections • It is not current with the newest technology

• Data that you develop yourself on-site will always be more meaningful. The drop-down menus allow you to select the type of safeguard class, type, and

description. When you do this, four different delay values (measured in seconds) will be shown at the top of the worksheet, corresponding to the equipment and materials that might be available to the inmate.

No Equip m en t Hand To ols Power T ools High Explosives

double click to copy this value-> 30000 240 180 45

Safeguard Class: Safeguard Type: Access Delay Description

Bag Port Cover

1/4 inch steel

Appendix G of the handbook contains all of the information that is inside the lookup function, as a long series of tables.

Summary

Using the simplified version of EASI you are able to examine each element of the scenario, enter new values, and immediately determine the impact on the probability of interruption.

This will lead you to the critical element(s) that could reduce risk if you can find a way to change the detection, delay or response.

There is a more advanced version of EASI available to those who have the need and the confidence to try it. The advanced program is different from the simplified version because:

• It starts with a complete ASD (adversary sequence diagram) that describes all elements the PPS and facility

• It analyzes the ASD and creates all of the potential pathways and calculates the corresponding probability of interruption

The advanced EASI version is actually contained in the simplified version, but it is hidden.

To reveal the advanced EASI worksheets: 1. Click on “Format”

2. Click on “Sheet” 3. Click on “Unhide”

4. Click on “Multipath Inputs”

A large colored screen will appear, which is the multipath input worksheet. You will need to repeat the steps above and click on “Results” to reveal the second worksheet that is part of the advanced EASI program.