Any negotiation will decay if you get into a yes/no frame. Too short/not too short is one of those cases. Any time you have a case where only one party can get what they want and the other party will sacrifice something major, you'll find the other party fighting hard. The goal is generally to move the discussion to a frame of reference where you can come to an agreement that lets both sides get something important and give up something that is minor compared to what you get.
Research
First, it always helps to know as much as possible when starting a negotiation. Questions for a schedule negotiation that I'd want to have in hand before returning to the negotiating table are -
Critical Path and/or Must Do Features
What's your critical path and what is the time burden of must do features that aren't on the critical path?
Chances are, you've sat down with the team already and figured this out. Always there is some set of tasks out there that simply cannot be done in parallel - you need the finished product to be able to do the next step and parts of that finished product have some unchangeable qualities. In particular, note things like:
- What are the must-have's are for completing critical steps?
- Any externally mandated wait points with estimates based on previous experience
- Ideas for where you can nestle other must-have items in the plan
- Areas of high risk to cost or schedule
Having this list written out moves you out of a can/can't discussion pretty quickly. It will also point out whether "having everyone work overtime" is even a viable solution. There's always the "9 women cannot birth a baby in 1 month" argument, but you can't say that until you really know what the path looks like.
Why the deadline?
Deadlines can happen for all sorts of reasons and only one of them is "because our project manager is out of his mind". Frequently that's the first impression I have.. but in reality, the overarching business drivers can be anything from a very finite mandate from a high priority customer to a general sense that if you don't get into the market with a certain feature, the value of product will collapse.
Get the scoop, preferably from more than one person. The manager you're arguing with is a key person, but also if there are others on the business end that can give a different persepctive, - get as much insight as possible.
A corallary here is "what REALLY needs to be done?" - it's not unusual for there to be serious disconnect between the "easy" feature the PM sees, and the "way hard" feature the technical team sees. What is really needed here and how simple can you make it?
What are the individual benefits to accomplishing the impossible?
Like the need for the deadline, every company will address this differently... but it could be anything, including:
- Covered by overtime pay
- Incentivized in yearly bonuses
- Something you can be fired for if you don't do
- A case where the business is in enough trouble that it's make or break for the company as a whole.
Is the team up for a push?
If this is a common issue, and you constantly operate in overload, then the answer may be "No", but if not, chances are, you have some team members more willing to take on the impossible than others... it's worth having a conversation on it, at the very least. It is probably best 1-on-1 between the people on the team and their manager.
Negotiation
Once you've got the information, you're in a better position to discuss the problem. Assuming the deadline is there for a reason, talk through the following with the manager responsible for the deadline:
- Limited scope - can you slim the work down to something you CAN achieve in 3 weeks?
- Added assistance for external delays - anything not linked to the team's work - can it be accelerated? A 2 week lag on a 3 week project because of external wait times is unacceptable, what can the management do to accelerate it or give relief if the delay happens
- Other aspects of potential schedule risk
- Ways to pay in cost to make up for pressure in schedule - temporary employees, overtime bonuses, other perks.
- Post-project recovery - pressure for 3 weeks isn't crazy if you know you have slack after that to recoup. This is both personal time (a day off with family), and work space cleanup time - chances are that other work slacked while you were meeting the deadline - what are the options to go back and cleanup when you've met the deadline?
Overtime
Overtime is a tricky one. In most professional, salaried environments I've seen, occasional overtime is an expectation. How occasional and how much overtime can vary wildly, but it is a common thing in many work spaces and the ways the expectation is raised and how strongly the requirement is worded will vary quite a bit from company to company and even boss to boss.
So - there's no easy answer here.
Your best bet is to know:
- the standards for your local industry and profession
- your own level of willingness at this time, and in this company
- whether or not overtime will help in a given situation
In the end, if you are working way more hours than is standard for your location/industry/profession - you may want to consider other employment options. Particularly if this is a big deal for your personal/family life. A single case of overtime is probably not a big reason to quit, but an ongoing pattern may be. It will have to be your call - it's a very personal choice.