Kế toán, kiểm toán - Chapter 5: Cost behavior: analysis and use

Cost Behavior: Analysis and UseChapter 5Learning Objective 1Understand how fixed and variable costs behave and how to use them to predict costs.A variable cost is a cost whose total dollar amount varies in direct proportion to changes in the activity level. Types of Cost Behavior Patterns – Variable The Activity Base (also called a cost driver)A measure of what causes the incurrence of a variable costUnitsproducedMiles drivenMachine hoursLabor hoursMinutes TalkedTotal Overage Charges on Cell Phone BillTrue Variable Cost – An ExampleAs an example of an activity base, consider overage charges on a cell phone bill. The activity base is the number of minutes used above the allowed minutes in the calling plan.Variable costs remain constant if expressed on a per unit basis.Types of Cost Behavior Patterns – Variable Minutes TalkedPer MinuteOverage ChargeVariable Cost Per Unit – An Example Referring to the cell phone example, the cost per overage minute is constant, for example 45 cents per overage minute.Extent of Variable CostsThe proportion of variable costs differs across organizations. For example . . . A public utility like Florida Power and Light,with large investments in equipment, will tend to have fewer variable costs.A manufacturing companylike Black and Deckerwill often have manyvariable costs.A merchandising companylike Wal-Martusually has a highproportion of variable costs,like cost of sales.Some service companies have high variable costs, while other service companies have highfixed costs.Examples of Variable CostsMerchandising companies – cost of goods sold.Manufacturing companies – direct materials, direct labor, and variable overhead.Merchandising and manufacturing companies – commissions, shipping costs, and clerical costs such as invoicing.Service companies – supplies, travel, and clerical.VolumeCostTrue Variable Costs The amount of a true variable cost used during the period varies in direct proportion to the activity level. The overage charge on a cell phone bill was one example of a true variable cost. Direct material is another example of a cost that behaves in a true variable pattern.Step-Variable CostsA step-variable cost is a resource that is obtainable only in large chunks (such as maintenance workers) and whose costs change only in response to fairly wide changes in activity.VolumeCostStep-Variable CostsSmall changes in the level of production are not likely to have any effect on the number of maintenance workers employed.VolumeCostStep-Variable CostsVolumeCostOnly fairly wide changes in the activity level will cause a change in the number of maintenance workers employed.RelevantRangeA straight line closely approximates a curvilinear variable cost line within the relevant range. ActivityTotal CostEconomist’sCurvilinear Cost FunctionThe Linearity Assumption and the Relevant RangeAccountant’s Straight-Line Approximation (constant unit variable cost)A fixed cost is a cost whose total dollar amount remains constant as the activity level changes.Types of Cost Behavior Patterns – Fixed Number of Minutes Used within Monthly Plan Monthly Basic Cell Phone BillTotal Fixed Cost – An Example For example, your cell phone bill probably includes a fixed amount related to the total minutes allowed in your calling plan. The amount does not change when you use more or less allowed minutes.Average fixed costs per unit decrease as the activity level increases.Types of Cost Behavior Patterns – Fixed Number of Minutes Used within Monthly PlanCost Per Cell Phone CallFixed Cost Per Unit Example For example, the fixed cost per minute used decreases as more allowed minutes are used.ExamplesAdvertising and Research and DevelopmentExamplesDepreciation on Buildings and Equipment and Real Estate TaxesTypes of Fixed CostsDiscretionaryMay be altered in the short-term by current managerial decisionsCommittedLong-term, cannot be significantly reduced in the short term.The Trend Toward Fixed CostsThe trend in many industries is toward greater fixed costs relative to variable costs.As machines take overmany mundane taskspreviously performedby humans, “knowledge workers”are demanded fortheir minds ratherthan their muscles.Knowledge workerstend to be salaried,highly-trained anddifficult to replace. Thecost of compensatingthese valued employeesis relatively fixedrather than variable.1Is Labor a Variable or a Fixed Cost?The behavior of wage and salary costs can differ across countries, depending on labor regulations, labor contracts, and custom.In France, Germany, China, and Japan, management has little flexibility in adjusting the size of the labor force.Labor costs are more fixed in nature.In the United States and the United Kingdom, management has greater latitude. Labor costs are more variable in nature.Within countries managers can view labor costs differentlydepending upon their strategy. Most companies in the United States continue to view direct labor as a variable cost.Rent Cost in Thousands of Dollars 0 1,000 2,000 3,000  Rented Area (Square Feet)03060Fixed Costs and the Relevant Range90 Relevant RangeThe relevant range of activity for a fixed cost is the range of activity over which the graph of the cost is flat.Fixed Costs and the Relevant Range Fixed costs would increase in a step fashion at a rate of $30,000 for each additional 1,000 square feet. For example, assume office space is available at a rental rate of $30,000 per year in increments of 1,000 square feet. How does this step-function pattern differ from a step-variable cost?Step-variable costs can be adjusted more quickly as conditions change and . . .The width of the activity steps is much wider for the fixed cost.Fixed Costs and the Relevant RangeQuick Check  Which of the following statements about cost behavior are true?Fixed costs per unit vary with the level of activity.Variable costs per unit are constant within the relevant range.Total fixed costs are constant within the relevant range.Total variable costs are constant within the relevant range. Which of the following statements about cost behavior are true?Fixed costs per unit vary with the level of activity.Variable costs per unit are constant within the relevant range.Total fixed costs are constant within the relevant range.Total variable costs are constant within the relevant range.Quick Check Fixed MonthlyUtility ChargeVariable Cost per KWActivity (Kilowatt Hours) Total Utility CostXYA mixed cost contains both variable and fixed elements. Consider the example of utility cost. Mixed Costs (also called semivariable costs) Total mixed cost Mixed Costs Fixed MonthlyUtility ChargeVariable Cost per KWActivity (Kilowatt Hours) Total Utility CostXYTotal mixed cost Mixed Costs – An ExampleIf your fixed monthly utility charge is $40, your variable cost is $0.03 per kilowatt hour, and your monthly activity level is 2,000 kilowatt hours, what is the amount of your utility bill?Analysis of Mixed CostsIn account analysis, each account is classified as either variable or fixed basedon the analyst’s knowledge of how the account behaves.The engineering approach classifies costs based upon an industrial engineer’s evaluation of production methods, and material, labor and overhead requirements.Account Analysis and the Engineering ApproachLearning Objective 2Use a scattergraph plot to diagnose cost behavior.Plot the data points on a graph (Total Cost Y vs. Activity X).0 1 2 3 4*Maintenance Cost1,000’s of Dollars10200*********Patient-days in 1,000’sXYThe Scattergraph MethodThe Scattergraph MethodDraw a line through the data points with about anequal numbers of points above and below the line. 0 1 2 3 4*Maintenance Cost1,000’s of Dollars10200*********Patient-days in 1,000’sXYThe Scattergraph MethodUse one data point to estimate the total level of activity and the total cost. Intercept = Fixed cost: $10,0000 1 2 3 4*Maintenance Cost1,000’s of Dollars10200*********Patient-days in 1,000’sXYPatient days = 800Total maintenance cost = $11,000The Scattergraph MethodMake a quick estimate of variable cost per unit and determine the cost equation. Variable cost per unit = $1,000 800= $1.25/patient-dayY = $10,000 + $1.25XTotal maintenance costNumber of patient daysLearning Objective 3Analyze a mixed cost using the high-low method.The High-Low Method – An ExampleAssume the following hours of maintenance work and the total maintenance costs for six months. The High-Low Method – An ExampleThe variable cost per hour of maintenance is equal to the change in cost divided by the change in hours.= $6.00/hour$2,400 400The High-Low Method – An ExampleTotal Fixed Cost = Total Cost – Total Variable CostTotal Fixed Cost = $9,800 – ($6/hour × 850 hours)Total Fixed Cost = $9,800 – $5,100Total Fixed Cost = $4,700The High-Low Method – An ExampleY = $4,700 + $6.00XThe Cost Equation for MaintenanceQuick Check  Sales salaries and commissions are $10,000 when 80,000 units are sold, and $14,000 when 120,000 units are sold. Using the high-low method, what is the variable portion of sales salaries and commission? a. $0.08 per unit b. $0.10 per unit c. $0.12 per unit d. $0.125 per unit Sales salaries and commissions are $10,000 when 80,000 units are sold, and $14,000 when 120,000 units are sold. Using the high-low method, what is the variable portion of sales salaries and commission? a. $0.08 per unit b. $0.10 per unit c. $0.12 per unit d. $0.125 per unit Quick Check $4,000 ÷ 40,000 units = $0.10 per unitQuick Check  Sales salaries and commissions are $10,000 when 80,000 units are sold, and $14,000 when 120,000 units are sold. Using the high-low method, what is the fixed portion of sales salaries and commissions? a. $ 2,000 b. $ 4,000 c. $10,000 d. $12,000 Sales salaries and commissions are $10,000 when 80,000 units are sold, and $14,000 when 120,000 units are sold. Using the high-low method, what is the fixed portion of sales salaries and commissions? a. $ 2,000 b. $ 4,000 c. $10,000 d. $12,000 Quick Check Least-Squares Regression MethodA method used to analyze mixed costs if a scattergraph plot reveals an approximately linear relationship between the X and Y variables.This method uses all of thedata points to estimatethe fixed and variablecost components of amixed cost.The goal of this method isto fit a straight line to thedata that minimizes thesum of the squared errors.Least-Squares Regression MethodSoftware can be used to fit a regression line through the data points.The cost analysis objective is the same: Y = a + bXLeast-squares regression also provides a statistic, called the R2, which is a measure of the goodnessof fit of the regression line to the data points. 0 1 2 3 4Total Cost10200Activity**********Least-Squares Regression MethodR2 is the percentage of the variation in the dependent variable (total cost) that is explained by variation in the independent variable (activity). R2 varies from 0% to 100%, andthe higher the percentage the better.XYComparing Results From the Three MethodsThe three methods just discussed provide slightly different estimates of the fixed and variable cost components of the mixed cost.This is to be expected because each method uses differing amounts of the data points to provide estimates.Least-squares regression provides the most accurate estimate because it uses all the data points.Learning Objective 4Prepare an income statement using the contribution format.Let’s put our knowledge of cost behavior to work by preparing a contribution format income statement. The Contribution FormatThe Contribution FormatThe contribution margin format emphasizes cost behavior. Contribution margin covers fixed costs and provides for income.Uses of the Contribution Format The contribution income statement format is used as an internal planning and decision-making tool. We will use this approach for:Cost-volume-profit analysis (Chapter 6).Budgeting (Chapter 9).Segmented reporting of profit data (Chapter 12).Special decisions such as pricing and make-or-buy analysis (Chapter 13).The Contribution FormatUsed primarily forexternal reporting.Used primarily bymanagement.Least-Squares Regression ComputationsAppendix 5ALearning Objective 5Analyze a mixed cost using the least-squares regression method.Simple Regression Analysis – An ExampleMatrix, Inc. wants to know its average fixed cost and variable cost per unit. Using the data to the right, let’s see how to do a regression using Microsoft Excel.Simple Regression Using Excel – An ExampleYou will need three pieces of information from your regression analysis:Estimated Variable Cost Per Unit (line slope)Estimated Fixed Costs (line intercept)Goodness of fit, or R2To get these three pieces information we will need to use three Excel functions.SLOPE, INTERCEPT, and RSQSimple Regression Using Excel – An ExamplePlace your cursor in cell F4 and press the = key. Click on the pull down menu and scroll down to “More Functions . . .”Scroll down to the “Statistical”, functions. Now scroll down the statistical functions until you highlight “SLOPE”Simple Regression Using Excel – An Example1. In the Known_y’s box, enter C4:C19 for the range.2. In the Known_x’s box, enter D4:D19 for the range. Simple Regression Using Excel – An ExampleHere is the estimate of the slope of the line.Simple Regression Using Excel – An Example1. In the Known_y’s box, enter C4:C19 for the range.2. In the Known_x’s box, enter D4:D19 for the range. With your cursor in cell F5, press the = key and go to the pull down menu for “Special Functions.” Select Statistical and scroll down to highlight the INTERCEPT function.Simple Regression Using Excel – An Example1. In the Known_y’s box, enter C4:C19 for the range.2. In the Known_x’s box, enter D4:D19 for the range. Here is the estimate of the fixed costs.Simple Regression Using Excel – An ExampleFinally, we will determine the “goodness of fit”, or R2, by using the RSQ function.Simple Regression Using Excel – An Example1. In the Known_y’s box, enter C4:C19 for the range.2. In the Known_x’s box, enter D4:D19 for the range. Here is the estimate of R2.Simple Regression Using Excel – An ExampleEnd of Chapter 5