Does your “To do list” behave like a Queue, a Stack, or a Priority Queue?

What is your “To do list”: A queue, a stack, or a priority queue?


In collaborative environments, people send and receive requests from many people. Individuals should process incoming requests and add them to their priority queue. Individuals should send descriptive requests to others with a clear deadline and level of importance.

What are Queues, Stacks, and Priority Queues?[1]

A queue is a line. For example, we enter a queue when we wait to pay for groceries. The person who enters the cashier line first will checkout first. A queue follows a “First In Last Out” or FIFO process.

A stack is a pile of items. For example, our email inbox is a stack, the newest email (Last in) is always at the top, usually read, deleted or archived first (First Out). A stack follows a “Last in First Out” or LIFO process.

A priority queue is a line with a set of rules that easily allows items to ‘skip ahead of the line’. For example, we enter a priority queue when we wait to board an airplane. The flight attendant allows the highest priority customer in the queue to board first. For instance, a business passenger will board before an economy passenger even if the economy passenger got in line 30 minutes earlier. A priority queue, unlike a queue, requires a set of rules to decide what is the highest priority. For example, who boards first when there are a handicap person, a passenger with a baby, and a business ticket passenger all in the queue?

What does our “to do list” look like?

Each morning there is a new set of requests waiting for our attention in different sources like (Facebook, Whatsapp, Asana, Email, media outlets, Waze, etc.) in addition to our existing ‘to do list’. How we handle the new batch of requests is critical to our long term performance.

We can add the requests to the top of our to do list (stack), add them to the bottom (queue) and risk missing something critical, or process the requests and add them to our priority queue. After processing, we can resume working on our top priority. Seems simple enough?

Here’s where and why I think it gets tricky

  1. How do I handle a request that does not include a priority level?

  2. How do I handle a request that is pushed compared to a request that is pulled when I’m ready to process the request?

The concept of “pushed” and “pulled” requests was first introduced to me when I got my first iPhone. My iPhone asked if I want email to be pushed to me as they are received or to be hidden from my view. The latter avoids new emails constantly distracting me. I can decide when to ‘pull’ the emails.

We are better off “pulling requests” at set times throughout the day than having requests pushed to us at all hours. However, as employees or service providers, our managers or clients are, of course, entitled to be make requests ‘on their time’.

As managers, we make requests of our employees often so that we can focus on other tasks. We rely on our employees or service providers to process the request, assign it a priority and implement it when it’s the highest priority item left in their queue. We should assign it a priority when we make the request but assigning it a priority is a tiring and exhausting process that requires more time from us.

As employees, we often *mistakenly* assume that the newest request from our manager is the most important unless otherwise stated. We become confused. We think to ourselves – my manager knows I can’t complete the other 3 requests she made yesterday and this new one. Obviously, she wants this one done first or she would have told me its priority level was lower. Further, how a boss issues a request (or instruction) implicitly assigns the task a level of priority:

  • If my manager sent the request on Slack, then the task must be Urgent;
  • If my manager sent the request via Email, then the task must be Urgent, but not as urgent as Slack.
  • If my manager sent the request via  Asana, he doesn’t think it’s as urgent.

Urgency does not imply Importance

Further, as employees, we confuse urgent with important. Slack may mean urgent but it doesn’t mean important. We mistakenly do the newest request;  effectively changing our to do list from a priority queue into a stack – a stack in which the important projects get hidden at the bottom.

What should we do to make sure our to do lists remain priority queues?

  1. When sending requests, always include a description explaining the importance and urgency. This means there should always be a deadline to a request.

  2. People should avoid pushing people requests that are not urgent. Managers may be better off adding the request to the meeting agenda or scheduling an email to send later in the day. For instance, managers can write an email at 6pm and schedule it to send at 7am so their employees can have a better work/life balance.

  3. Employees should make it know when they ‘pull requests’ e.g. 10am in person scrum + email processing.

  4. Employees should respond to a requestor with a recommended order of priorities so that a manager has transparency on how someone spends their time. This makes it easy for a manager to change priorities or juggle the requests being made of their direct report.

[1] These terms are commonly used to refer to Data Structures. See here for more on the topic

One thought on “Does your “To do list” behave like a Queue, a Stack, or a Priority Queue?

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s