

This example illustrates the use of the LAG= option to indicate nonstandard precedence relationships between activities. Consider
the widget manufacturing project described in the earlier examples. Some of the precedence constraints between the activities
may be nonstandard or have a nonzero lag value. For example, the activity 'Init. Prod.' may not be able to start until 2 days
after the completion of the activity 'Facility.' The Network data set is displayed in Output 9.6.1. The variable lagdur indicates the type of relationship between the activities specified in the variables task and succ.
The following statements invoke PROC NETDRAW with the LAG= option. The resulting network diagram is shown in Output 9.6.2.
pattern1 v=e c=green;
title h=3 'Widget Manufacture';
title2 h=2 'Nonstandard Precedence Constraints';
proc netdraw graphics data=widglag;
actnet / act=task
succ=succ
lag=lagdur
pcompress
htext=3 boxht=3 arrowhead=2
xbetween=7 ybetween=9
centerid
separatearcs;
run;
Output 9.6.1: Network with Nonstandard Precedence Constraints
| Widget Manufacture |
| Network Data Set |
| Obs | task | days | succ | lagdur |
|---|---|---|---|---|
| 1 | Approve Plan | 5 | Drawings | |
| 2 | Approve Plan | 5 | Study Market | |
| 3 | Approve Plan | 5 | Write Specs | |
| 4 | Drawings | 10 | Prototype | |
| 5 | Study Market | 5 | Mkt. Strat. | |
| 6 | Write Specs | 5 | Prototype | |
| 7 | Prototype | 15 | Materials | ss_9 |
| 8 | Prototype | 15 | Facility | ss_9 |
| 9 | Mkt. Strat. | 10 | Test Market | |
| 10 | Mkt. Strat. | 10 | Marketing | |
| 11 | Materials | 10 | Init. Prod. | |
| 12 | Facility | 10 | Init. Prod. | fs_2 |
| 13 | Init. Prod. | 10 | Test Market | |
| 14 | Init. Prod. | 10 | Marketing | |
| 15 | Init. Prod. | 10 | Evaluate | |
| 16 | Evaluate | 10 | Changes | ss_6 |
| 17 | Test Market | 15 | Changes | ff_3 |
| 18 | Changes | 5 | Production | |
| 19 | Production | 0 | ||
| 20 | Marketing | 0 |
Output 9.6.2: Network Diagram with Nonstandard Precedence Constraints
