What Is the 80-20 Rule?

The 80-20 rule, also known as the Pareto Principle, is a familiar saying that asserts that 80% of outcomes (or outputs) result from 20% of all causes (or inputs) for any given event.

In business, a goal of the 80-20 rule is to identify inputs that are potentially the most productive and make them the priority. For instance, once managers identify factors that are critical to their company’s success, they should give those factors the most focus.

Although the 80-20 rule is frequently used in business and economics, you can apply the concept to any field. Wealth distribution, personal finance, spending habits, and even infidelity in personal relationships can all be the subject of the 80-20 rule.

How Does the 80-20 Rule Work?

You may think of the 80-20 rule as simple cause and effect: 80% of outcomes (outputs) come from 20% of causes (inputs). The rule is often used to point out that 80% of a company’s revenue is generated by 20% of its customers.

Viewed in this way, it might be advantageous for a company to focus on the 20% of clients that are responsible for 80% of revenues and market specifically to them. By doing so, the company may retain those clients, and acquire new clients with similar characteristics. However, there’s a more fundamental meaning to the 80-20 rule.

Core Principle

At its core, the 80-20 rule is about identifying an entity’s best assets and using them efficiently to create maximum value. For example, a student should try to identify which parts of a textbook will create the most benefit for an upcoming exam and focus on those first. This does not imply, however, that the student should ignore the other parts of the textbook.

Misinterpretations

People may not realize that the 80-20 rule is a precept, not a hard-and-fast mathematical law. Furthermore, it is isn’t necessary that the percentages equal 100%. Inputs and outputs simply represent different units. The percentages of these units don’t have to add up to 100%. It’s the concept behind the rule that matters.

There’s another way in which the 80-20 rule is misinterpreted. Namely, that if 20% of inputs are most important, then the other 80% must not be important. This is a logical fallacy. The 80% can be important, even if the decision is made to prioritize the 20%.

80-20 Rule Background

The 80-20 rule is also known as the Pareto principle and is applied in Pareto analysis. It was first used in macroeconomics to describe the distribution of wealth in Italy in the early 20th century. It was introduced in 1906 by Italian economist Vilfredo Pareto, who is best known for the concepts of Pareto efficiency.

Pareto noticed that 20% of the pea pods in his garden were responsible for 80% of the peas. Pareto expanded this principle to macroeconomics by showing that 80% of the wealth in Italy was owned by 20% of the population.

In the 1940s, Dr. Joseph Juran, a prominent figure in the field of operations management, applied the 80-20 rule to quality control for business production.

He demonstrated that 80% of product defects were caused by 20% of the problems in production methods. By focusing on and reducing the 20% of production problems, a business could increase the overall quality of its products. Juran referred to this phenomenon as “the vital few and the trivial many.”

Benefits of the 80-20 Rule

Although there is little scientific analysis that either proves or disproves the 80-20 rule’s validity, there is much anecdotal evidence that supports the rule as being essentially valid, if not numerically accurate.

Performance results of salespeople in a wide range of businesses have demonstrated success by incorporating the 80-20 rule. In addition, external consultants who use Six Sigma and other management strategies have incorporated the 80-20 principle in their practices with good results.

Example of the 80-20 Rule

A Harvard graduate student, Carla, was working on an assignment for her digital communications class. The project was to create a blog and monitor its success during the course of a semester.

Carla designed, created, and launched the site. Midway through the term, the professor conducted an evaluation of the blogs. Carla’s blog, though it had achieved some visibility, generated the least amount of traffic compared with her classmates’ blogs.

Define the Problem

Carla happened upon an article about the 80-20 rule. It said that you can use this concept in any field. So, Carla began to think about how she might apply the 80-20 rule to her blog project. She thought, “I used a great deal of my time, technical ability, and writing expertise to build this blog. Yet, for all of this expended energy, I am getting very little traffic to the site.”

She now understood that even if a piece of content is spectacular, it is worth virtually nothing if no one reads it. Carla deduced that perhaps her marketing of the blog was a greater problem than the blog itself.

Apply the 80-20 Rule

To apply the 80-20 rule, Carla decided to assign her 80% to all that went into creating the blog, including its content. Her 20% would be represented by a selection of the blog’s visitors.

Using web analytics, Carla focused closely on the blog’s traffic. She asked herself:

• Which sources comprise the top 20% of traffic to my blog?
• Who are the top 20% of my audience that I wish to reach?
• What are the characteristics of this audience as a group?
• Can I afford to invest more money and effort into satisfying my top 20% readers?
• In terms of content, which blog posts constitute the top 20% of my best-performing topics?
• Can I improve upon those topics, and get even more traction from my content than I’m getting now?

Carla analyzed the answers to these questions, and edited her blog accordingly:

1. She adjusted the blog’s design and persona to align with her top 20% target audience (a strategy common in micromarketing).
2. She rewrote some content to meet her target reader’s needs more fully.

Significantly, although her analysis did confirm that the blog’s biggest problem was its marketing, Carla did not ignore its content. She remembered the common fallacy cited in the article—if 20% of inputs are most important, then the other 80% must be unimportant—and did not want to make that mistake. She knew it was necessary to address aspects of the content, as well.

Results

By applying the 80-20 rule to her blog project, Carla came to understand her audience better and therefore targeted her top 20% of readers more purposefully. She reworked the blog’s structure and content based on what she learned, and traffic to her site rose by more than 220%.

What Is Arc Elasticity?

Arc elasticity is the elasticity of one variable with respect to another between two given points. It is used when there is no general way to define the relationship between the two variables. Arc elasticity is also defined as the elasticity between two points on a curve.

The concept is used in both economics and mathematics. In economics, is it commonly used to measure the changes between the quantity of goods demanded and their prices.

Understanding Arc Elasticity

In economics, arc elasticity is commonly used in relation to the law of demand to measure percentage changes between the quantity of goods demanded and prices.

There are two possible ways of calculating elasticity—price (or point) elasticity of demand and arc elasticity of demand. Price elasticity of demand measures the responsiveness of quantity demanded to a price. It takes the elasticity of demand at a particular point on the demand curve, or between two points on the curve. Arc elasticity of demand uses a midpoint between the two points.

Formula for Price (Point) Elasticity of Demand


$PE_d = \dfrac{\text{\% Change in Qty}}{\text{\% Change in Price}}$PEd​=% Change in Price% Change in Qty​

How to Calculate the Price Elasticity of Demand

If the price of a product decreases from $10 to $8, leading to an increase in quantity demanded from 40 to 60 units, then the price elasticity of demand can be calculated as:

• % change in quantity demanded = (Qd₂ – Qd₁) / Qd₁ = (60 – 40) / 40 = 0.5
• % change in price = (P₂ – P₁) / P₁ = (8 – 10) / 10 = -0.2
• Thus, PE_d= 0.5 / -0.2 = 2.5

Since we’re concerned with the absolute values in price elasticity, the negative sign is ignored. You can conclude that the price elasticity of this good, when the price decreases from $10 to $8, is 2.5.

Arc Elasticity of Demand

One of the problems with the price elasticity of demand formula is that it gives different values depending on whether price rises or falls. If you were to use different start and end points in our example above—that is, if you assume the price increased from $8 to $10—and the quantity demanded decreased from 60 to 40, the Pe_d will be:

• % change in quantity demanded = (40 – 60) / 60 = -0.33
• % change in price = (10 – 8) / 8 = 0.25
• PE_d = -0.33 / 0.25 = 1.32, which is much different from 2.5

How to Calculate the Arc Elasticity of Demand

To eliminate this problem, the arc elasticity of demand can be used. Arc elasticity of demand measures elasticity at the midpoint between two selected points on the demand curve by using a midpoint between the two points. The arc elasticity of demand can be calculated as:

• Arc E_d = [(Qd₂ – Qd₁) / midpoint Qd] ÷ [(P₂ – P₁) / midpoint P]

Let’s calculate the arc elasticity following the example presented above:

• Midpoint Qd = (Qd₁ + Qd₂) / 2 = (40 + 60) / 2 = 50
• Midpoint Price = (P₁ + P₂) / 2 = (10 + 8) / 2 = 9
• % change in qty demanded = (60 – 40) / 50 = 0.4
• % change in price = (8 – 10) / 9 = -0.22
• Arc E_d = 0.4 / -0.22 = 1.82

When you use arc elasticity of demand you do not need to worry about which point is the starting point and which point is the ending point since the arc elasticity gives the same value for elasticity whether prices rise or fall.

The Bottom Line

Arc elasticity is commonly used in economics to determine the percentage of change between the demand for goods and their price. Elasticity can be calculated in two ways—price elasticity of demand and arc elasticity of demand. The latter is more useful when there is a significant change in price.

What Is the American Opportunity Tax Credit (AOTC)?

The American Opportunity Tax Credit (AOTC) is a tax credit for qualified education expenses associated with the first four years of a student’s postsecondary education. The maximum annual credit is $2,500 per eligible student. The student, someone claiming the student as a dependent, or a spouse making postsecondary education payments can claim the AOTC on their tax return.

Understanding the American Opportunity Tax Credit (AOTC)

With the AOTC, a household with a qualifying student can receive a maximum $2,500 tax credit per year for the first four years of higher education. Parents claiming a dependent child who is a full-time student ages 19 to 24 can claim an additional $500 Child Tax Credit.

The AOTC helps with educational costs such as tuition and other expenses related to a student’s coursework. Eligible students (or their parents) can claim 100% of the first $2,000 spent on school expenses and 25% of the next $2,000. This comes out to a maximum credit of $2,500: (100% × $2,000) + (25% × $2,000).

In general, tax credits are refundable, nonrefundable, or partially refundable. Up to $1,000 (40%) of the AOTC is refundable, making it a partially refundable tax credit. So, if the credit brings your tax liability to $0, you can receive 40% of your eligible credit (up to $1,000) as a refund.

AOTC Eligibility Requirements

Like other tax credits, you must meet specific eligibility requirements to claim the AOTC.

Who Can Claim the AOTC?

To claim the AOTC on your tax return, you must meet all three of these requirements:

• You pay qualified education expenses for higher education.
• You pay the education expenses for an eligible student.
• The eligible student is either you, your spouse, or a dependent whom you claim on your tax return.

Additionally, you must receive Internal Revenue Service (IRS) Form 1098-T to claim the credit. Here’s an example of a completed form:

Source: Internal Revenue Service

Which Students Qualify for the AOTC?

A student is eligible for the AOTC only if they meet certain requirements. Specifically, the student must:

• Be taking courses toward a degree or some other recognized education qualification
• Be enrolled at least part time for at least one academic period beginning in the tax year
• Not have finished the first four years of higher education at the beginning of the tax year
• Not have claimed the AOTC (or the former Hope credit) for more than four tax years
• Not have a felony drug conviction at the end of the tax year

Which Expenses Qualify for the AOTC?

For the purposes of the AOTC, qualified education expenses include tuition and some related costs required for attending an eligible educational institution. An eligible educational institution is any accredited public, nonprofit, or private college, university, vocational school, or other postsecondary educational institution. Related expenses include:

• Student activity fees paid to the school as a condition of enrollment or attendance
• Books, supplies, and equipment needed for classes, whether or not you buy them from the school

You can pay for qualified education expenses with student loans. However, you can’t claim the credit if you paid for expenses with scholarships, grants, employer-provided assistance, or funds from a 529 savings plan.

What Are the Income Limits for the AOTC?

To claim the full credit, your modified adjusted gross income (MAGI) must be $80,000 or less ($160,000 if married filing jointly). The credit begins to phase out above these limits and disappears entirely if your MAGI is above $90,000 ($180,000 for married filing jointly).

What Is Aggregate Stop-Loss Insurance?

Aggregate stop-loss insurance is a policy designed to limit claim coverage (losses) to a specific amount. This coverage ensures that a catastrophic claim (specific stop-loss) or numerous claims (aggregate stop-loss) do not drain the financial reserves of a self-funded plan. Aggregate stop-loss protects the employer against claims that are higher than expected. If total claims exceed the aggregate limit, the stop-loss insurer covers the claims or reimburses the employer.

Understanding Aggregate Stop-Loss Insurance

Aggregate stop-loss insurance is held for self-funded insurance plans for which an employer assumes the financial risk of providing healthcare benefits to its employees. In practical terms, self-funded employers pay for each claim as it is presented instead of paying a fixed premium to an insurance carrier for a fully insured plan. Stop-loss insurance is similar to purchasing high-deductible insurance. The employer remains responsible for claim expenses under the deductible amount.

Stop-loss insurance differs from conventional employee benefit insurance. Stop-loss only covers the employer and provides no direct coverage to employees and health plan participants.

How Aggregate Stop-Loss Insurance Is Used

Aggregate stop-loss insurance is used by employers as coverage for risk against a high value of claims. Aggregate stop-loss insurance comes with a maximum level for claims. When a maximum threshold is exceeded, the employer no longer needs to make payments and may receive some reimbursements.

Aggregate stop-loss insurance can either be added to an existing insurance plan or purchased independently. The threshold is calculated based on a certain percentage of projected costs (called attachment points)—usually 125% of anticipated claims for the year.

An aggregate stop-loss threshold is usually variable and not fixed. This is because the threshold fluctuates as a percentage of an employer’s enrolled employees. The variable threshold is based on an aggregate attachment factor which is an important component in the calculation of a stop-loss level.

As is the case with high deductible plans, most stop-loss plans will have relatively low premiums. This is because the employer is expected to cover over 100% of the value of claims they receive.

Aggregate Stop-Loss Insurance Calculations

The aggregate attachment associated with a stop-loss plan is calculated as follows: 

Step 1

The employer and stop-loss insurance provider estimate the average dollar value of claims expected by employee per month. This value will depend on the employer’s estimate but often ranges from $200 to $500 per month.

Step 2

Assume the stop-loss plan uses a value of $200. This value would then be multiplied by the stop-loss attachment multiplier which usually ranges from 125% to 175%. Using a claims estimate of $200 and a stop-loss attachment multiplier of 1.25, the monthly deductible would be $250 per month per employee ($200 x 1.25 = $250).

Step 3

This deductible must then be multiplied by the employer’s plan enrollment for the month. Assuming that an employer has 100 employees in the first month of coverage, their total deductible would be $25,000 for the month ($250 x 100).

Step 4

Enrollment can potentially vary per month. Due to enrollment variance, aggregate stop-loss coverage may have either a monthly deductible or an annual deductible.

Step 5

With a monthly deductible, the amount an employer must pay could change every month. With an annual deductible, the amount the employer must pay would be summed for the year and usually based on estimates from the initial month of coverage. Many stop-loss plans will offer an annual deductible that is slightly lower than the summation of deductibles over 12 months.