Joanne, it was an opportunity you for bringing up these topics here.

Here are my thoughts and opinions regarding what you brought up, with the support of OpenAI's Artificial Intelligence. 1. **Top Down vs Bottom Up Scheduling:**   I've noted that both Vladimir Liberzon and Alex Wong provided valuable insights into this debate. Vladimir emphasized the importance of bottom up scheduling for precise control and detailed oversight. Alex acknowledged the utility of top down scheduling in quickly developing tender programs and gaining an overall vision, especially when information is limited. While each approach has its merits, the choice largely depends on the specific context of your project and the level of detail required. However, it’s crucial that the company pushing for a top down approach presents concrete evidence and past results demonstrating its effectiveness and efficiency. This would help in understanding the rationale behind their directive and ensure that it’s not merely a theoretical preference but a proven strategy. 2. **Logic at Multiple Levels of the Schedule:**   Both Vladimir and Alex suggest minimizing complexity in scheduling logic. Vladimir stresses the need for logic at the lowest level to maintain visibility of the critical path and to avoid issues when progress deviates from the plan. Alex adds that the extent of logic should correlate with the time available for schedule updates. In your case, allowing the company to justify their multi-level logic approach with real-world examples and successes would be beneficial. It would provide clarity and potentially highlight the practical advantages they foresee. 3. **Finish to Start Logic with Negative Lag:**   Vladimir and you both share a dislike for negative lags, highlighting their potential to create confusion and inaccuracies. Using more appropriate predecessors and positive lags, as you suggest, often results in a clearer and more reliable schedule. The company's directive to use such practices should come with substantial backing. They should present scenarios where this approach has led to better outcomes, demonstrating its reliability and benefit over traditional methods. In conclusion, while it's valuable to debate these methodologies, it’s imperative that the company enforcing these changes steps forward. They should provide evidence of their competence and credentials, show historical data where their directives have produced positive results, and engage in this discussion to justify their approach. This transparency will foster trust and ensure that all stakeholders are aligned towards a common goal of effective project management. Additionally, I was invited to participate in this discussion by Alex Yatschenko, which underscores the importance and relevance of these topics within our professional community.  **My Personal Opinion:**In my view, there are many ideas and techniques learned in courses or within academic settings that are not practical or feasible in real-world applications. Often, this theoretical knowledge overlooks the practical insights and experiences of those who are actively working in the field. It is essential to bridge this gap by combining theoretical knowledge with practical expertise to develop realistic and effective project management strategies. I recommend bringing the person or professional who deemed this directive as the correct and professional technique into this discussion. They should justify and explain the reasons and the guaranteed success that adopting the top down approach will bring.    


Here are my ideas and opinions. To truly understand the limits and capabilities of the Primavera tool, it would be interesting to watch the 16-minute video I recently produced.

https://youtu.be/A1rf_El6peI
https://youtu.be/j1LVZk6NlBU
 

Vladimir,

You are right, in version 4.0 Primavera included a resource as materials

Cheers

Alex

Alex,
it is a hard task. I am sure that PM software should be supported on site. It is not the same as promoting word processor. We want to be sure that our customers use Spider Project properly and as in Russia using Spider Project means a good project management in the company. We start to sell at the new markets if we have good partners there. Now we have such partners in Ukraine, Belorussia, Romania. We also sell the package to people from other countries who had found the package in the Internet - usually these people have proper qualification and we keep the contact and support them not only answering the questions but suggesting our advises on methodology and project management issues.
Entering other markets without local partners in a proper way (with local representatives, courses, support, promotion) is too expensive. We are not that rich and too busy because the Russian market is very fast growing. In 1993 when the first Spider version was suggested to the local market few people had the knowledge of what is project management. Now project management is hot. More and more companies implement PM and besides here Spider Project is used for resource management in manufacturing.
But you are right - we shall think about it and make more efforts in finding proper partners abroad.
Best Regards,
Vladimir

Luca,
here they use Spider and transfer projects to Primavera if the customer wants it. Nobody use both programs in parallel. Spider is more powerful, has many additional features and fields. As the result in this transfer some Spider data are lost. I mean activity volumes, resource productivities, cost components, assignment costs, resource material requirements, multiresources and assignment pools, additioanal WBS, etc. Transfering data back and forth you will not use many useful Spider Project features. The data exported into Primavera are transformed according to P3e capabilities. You can restore Spider data using references but it is an additional work.
So I don’t support an idea to use both systems in the same projects. Here people usually move to Spider when Primavera or Open Plan resource and cost management capabilities are not sufficient to their projects. Many Spider Project users started with using MS Project (as everywhere). It should be necessary, if the need is not conscious then changing the software tools does not make sense.

In Russia some foreign clients like Washington Group or Parsons also require the project information in P3e format. Those who use Spider just export projects to P3e for these customers.
There is another interesting problem about which I wrote previously. Internal schedule is not intended for the customers. The schedule you use for reporting to your partners and the schedule you use for setting tasks are different. In Spider Project you can use different schedules for the same project and just export performance data from one project model to another. You don’t need to enter project performance data several times.
Is this problem (parallel schedules) actual for everybody? What do you do?

David,
you can download Spider Project Demo (40 tasks restriction) and User Guide from http://www.spiderproject.ru/spider_e.shtml and some corresponding publications from http://www.spiderproject.ru/publ_e.shtml#eng
Demo includes sample projects. I will be glad to answer your questions and to learn your opinion. Demo version does not include some features like export/import to and from MS Project and Primavera, work with Internet, but main functionality is full.
Pay attention to resource leveling. Spider Project optimizes resource constrained schedules and takes into account financial and supply restrictions. Create as many WBS for the same project as you need.
If you will think that the package cannot do something useful - just ask (my E-mail: v_liberzon@yahoo.com). Some solutions are not traditional.
Enjoy,
Vladimir

To Joanne and David:
In Spider Project we use volume lags - if some volume was done then the next activity can be performed (for example - if 500 m of ditching was done then the welding can start).
It is more reliable than % lag - it is hard to define EV % complete collecting performance data.
The only example of SF relationship that we usually use:
Hammock (LOE) task (project management activity for an example) will finish after the project object will start to function (shop starts to earn money or something like that).
Vladimir

I think your partly right, and alos partly wrong. But then is all a game isn’t it? Everyone does it differently.

Level 3 = Engineering CTRs for Each Platform

Level 2 = Key Activities for Each Discipline in each platfrom

Level 1 = Key Dates for each Platform

BUT where we differ, is that I do not believe that these should be separated from contractual detail.
All the contractual milestones and contingencies SHOULD be built into your plan. That way you can advise your own management and the client where REAL criticality exists.

Anyway, let me know what you think as this is getting inetersting!!

Joanne, was your last for me or Vladimir?

David,
thank you for your reply. But I still insist that levels 1 and 2 are not just roll ups but different schedules that define project contract targets. Internal schedules should have different target dates and costs that don’t allow for contingency and management reserves included in the contract schedules. If they are just roll ups then it is just a matter of reporting and the schedule is the same for all levels. Is it correct?

Contract conditions define target dates and costs for major deliverables.
The internal working schedule created by the contractor should have reasonable reserves to be sure that the contract conditions will be met.
We usually define a set of targets - contract targets, management targets (include managenet and contingency reserves), project management team targets (include contingency reserves), project team targets (do not include reserves - optimistic schedule).
So if I understood correctly then Level 1 and Level 2 schedules are created for the contract negotiations and reporting and represent contract target dates of major deliverables. Working contractor schedule may be quite different.

Joanne,
this is an interesting question - what is level 3 schedule? I don’t understand why there is a need to create schedule levels. You can present a reports with the different levels of detail - to show 2, 3, 4th, etc. levels of WBS but in the same schedule!

Okay - think of scheduling meetings into an engineering programme, say QA audits for Piping. These are usually time to coincide with the issue of certain deliverales, or studies. Do you think it would be good planning practive to use a FS-ve lag in such an instance to determine the timing of the meeting.

(Assume that the schedule is a Level 3 and connot be broken down any further.)

After reading the link from Joanne (and it was a good read! :¬) I would even be tempted to use SF, to allow the meting to be scheduled without being included in total float calcs.

Joanne
I am not total agree with you on SS + Lag can be replace by FS - Lag

Ie if I have an activity where the original plan duration is 100 days and said I can only start the activity 50 days prior to it’s finish. ie 50 days before the store opening I will plant the flowers in the garden so that the flowers will blooming for the next 3 months after the opening date.

If base on what you stated I can use SS with + lag with 50 days. If I started the activity at day "1" and after 30 days the project manager told me that the opening date can be bring forward and he estimate the remaining durtion is 50 days and the activity is not 50% complete. Should I start plant the flowers?? with SS the logic , the activity will not start for another 20 days but if I use Finish to Start with -50 days then I should start.

I guess in real life if the activity is rely on the finish date then the logic better stay with the finish date. Because a plan is a plan once it kick off, conditions will vary and you may not remember the reason why you change the FS with a SS.

Again this problem can be solve by having the activity breakdown futher so that it become a FS without any lag.

Yeh - seemed odd, BUt appeared to work. I take that the % lag you mention is a function of either P£e or some other planning package, as we don not have that facility in the version of P3 we use (3.1). But I like the idea.

SS+ve lag is always best as it is definable logic, even better to break it down further.

One other question I would love answered is has anyone ever used the SF link method in any schedule they know of. I was talking to my compadres in planning here in London, and they were keen to find out.

Recently cam across a sample of FS-ve lag that ’appeared’ to be usefull.

PDMS modelling for Piping on offshore structure on a Lev3l 3 plan.

PDMS is the computer model for the platform, progressed through various tages A thru to E with E being 100% in a stepped planned approach. Code E = 100% of Isos 100% complete

Each step was FS with a -ve lag, and as each step missed its planned completion, it drove out the overall completion date for the Code E activity, which in turn reforecast the Isos completion.

Seemed a bit odd to me but appeared to do the trick as it not possible to break the schedule out any further. The guy who developed it has got about 35yrs experience as well, and claimed it was a standard way of scheduling this work. Only problem was the lag - how did he know it was a given. Any thoughts?

Martin, IMO, because the relationship does not represent "hard logic".

I would try breaking the predecessor activity down into more detail where a logical FS relationship may be established.

Bernard Ertl
InterPlan Systems - eTaskMaker Project Planning Software

Vladimir, how does your probablistic approach differ from PERT? It sounds like what you are describing.

Joanne, you may find this page interesting as it describes some of the shortcomings with PERT, Monte Carlo, etc. as risk analysis tools:

Scheduling with Uncertain Durations

FS relationships with negative lags (or SF relationships) do not represent hard logic for critical path analysis IMO. It is most often an artificial constraint used to gauge when to start a task for a JIT (just in time) process. In these cases, delaying tasks to the last moment it may distort float values and add risk to a project IMO. Sometimes that is acceptable depending upon business needs, but it is poor scheduling practice IMO.

Bernard Ertl
InterPlan Systems - eTaskMaker Project Planning Software

Joanne,
"the idea of having both top down logic and bottom up logic within the one schedule" may work only if all project phases should be performed only one after another, or are completely independent. In the real life it is rare.

If you will create milestones for the start and finish events for project phases then top down logic will link these milestones. Usually we recommend to do it because in another WBS structure linked phases do not exist.

If some work package is typical we recommend to create corresponding fragnet that should be stored in the corporate fragnet library. If the fragnet is used in some project then it is taken from the library and is implemented in the project model. Then fragnet activities should be linked with the activities of other fragnets in the project. Creating fragnet library is a good idea, but linking the fragnets and not the activities within fragnets is a bad one.

Why top down logic became necessary in your company?

Resource Constraints Logic

ie. say a contractor may decided to have 5 teams of workers to carryout 100 locations inidividually and each location take 10 days. If the schedule is breakdown into all 100 locations activities and the scheduler will linked them into five groups (5 teams) each will take 20 locations * 10 days = 200 days to finish the works. If each location is unique and your schedule is breakdown in to such details and track to these details then if anything out of synz, the scheduler require to reschedule the logic. In addition, during the EOT process the scheduler need to prove that the resource constraints is part of the critical path.

interested in others thoughts on:

- top down vs bottom up scheduling, which do you use and why

Top down will be good when you have to produce a tender programme in a short time. In addition, it also give the scheduler some thought as on the overall plan (High level vision) Especially when a lot of the team member is not yet recurited or info is not accesible (Production rate...)the best way is top down. Remember if both top down and bottom up, 1 thing that is very critical is how deep you want the drew down the schedule and how much effort you can spend to maintain the schedule. I came across lot of schedule that actually when too far and at the end never mean anything to the project manager because it is too out of date and can run any simple analysis to the schedule. So the start is very important to develop any form of schedule.

- do you allow logic at multiple levels of the schedule

As I state above, depend how much time you allow to update your schedule. If you allow four weeks per month to update, "yes" multi level and resource contrainted logic can be added to the schedule. Remember you need to change all the resource contraints as the site progress changes. However,if you only allow 1 week of your time to do the update then try to min. the number of logic especially resource contraints logics.

- your thoughts on Finish to Start logic with negative lag

I think there are occasions that you will need to use FS with neg lag. like prepare in a cable manuf. line, the next batch of production will start preparation two days before the last batch complete. However, this logic can be reschedule if you add additional activity at the end of the production then you can have a start - start relation without any - lag. If you do this to all the logic, again you increase the no of activity without gaining any benefits.

I guess the logic will never use is start finish. (Any suggestion?? PPs)

would love to hear thoughts on this from other experienced schedulers.

Thanks

Joanne,
you are right - logic is on the activity (or task) level. Links between phases are too rough approximations of the real life. Besides using our software you can use multiple WBS for the same project and you just will not be able to control these links in the alternative WBS. You can create rough schedule and then decompose activities in more detail. In this case you should reconsider links - they still should be used on the lowest level of decomposition.
Negative lag is something that should be avoided. Sometimes it is still necessary to use them but these situations are rare and should be rare.
I think that you should demonstrate the examples when top down logic does not work to the senior management. It may be useful to receive their support.