D4.2.9-12: Constructing Explanations Judged by Their Purpose

Overview

Lesson Procedure

75-80 minutes of class time across 5 phases.

1. Warm-Up10 minutes
2. Direct Instruction25-30 minutes
3. Guided Practice15 minutes
4. Independent Practice15 minutes
5. Closure10 minutes

1. Warm-Up10 minutes

   Warm-Up Prompt

   "Your school switched from paper report cards to an online grade portal. Write one sentence that explains why it switched, one that explains when each step happened, and one that explains how a teacher enters a grade. Which sentence would a parent want, and which would a new teacher want?"

   Collect one sentence of each kind. Name the purposes they serve: cause and effect (why), chronological (when, in order), procedural (the steps a person follows) and technical (how a device or system works). Introduce the indicator: a strong explanation is judged against its purpose, so a perfect timeline can still be a weak answer to a why question.

2. Direct Instruction25-30 minutes

   Part 1: The question and the sources. How did the Census Office count about 62 million people in 1890, and why did it change its methods? Sources 1-3 are the Census Bureau's history pages, revised in 2024. Source 4 is Hollerith's 1889 article, written to present his system before the count. Sources 5 and 6 come from an 1891 article by Thomas Commerford Martin in The Electrical Engineer, an electrical journal; he visited the Census Office and openly favored the machines.

   Source Information: who made each source, when, and what stake the maker had (from the sources themselves)

   Source	Maker and position	When	Stake or limit to keep in mind
   1: Early Census Processing	Census Bureau History Office	Page revised 2024	The agency describing its own past
   2: The Hollerith Machine	Census Bureau History Office	Page revised 2024	Gives contest results in hours without naming the two rivals
   3: Tabulation and Processing	Census Bureau History Office	Page revised 2024	Gives no figures for its claims about schedule and budget
   4: An Electric Tabulating System	Herman Hollerith, the inventor	1889, before the count	Describes his own invention; predictions, not results
   5 and 6: Counting a Nation by Electricity	T. C. Martin, writing in an electrical journal after visiting the Census Office	1891, during the tabulation	A supporter who quotes the critics only briefly

   Part 2: Read the sources. Students read in a jigsaw: one group per source pair (1 and 3, 2, 4, 5 and 6), then regroup to share. Terms: tabulate (count answers into tables), schedules (the census forms), enumerator (the person who collected the answers), pantograph (a hand punch that copied a hole pattern onto a card), mercury (a liquid metal that carries electric current), dwelling house count (the first count of households and persons), expeditious (fast and efficient).

   How the texts were prepared: Sources 1-3 are copied from census.gov; Sources 4-6 are typed exactly from the page scans of the 1889 and 1891 printings, and [...] marks every place where words are left out. In Source 5, "tabulasing" is the 1891 printer's misprint for tabulating; Hunt and Pidgin were the two rival entrants; Martin describes their plans in a part of his article not printed here.

   1Census officials have struggled to quickly and accurately process and tabulate census information since the first enumeration. From the 1790 census until the 1840 census, enumerators (in those days, assistant U.S. Marshals) collected information about the population in household units. Members of households were tallied based on their age, gender, and race. Clerks then hand-counted the tallies on each questionnaire sheet for each demographic category.

   2In 1850, census forms began collecting information on individuals. As the census form became more complicated, tallying census results became increasingly difficult. Census clerks still tabulated census data by hand, but began using increasingly complicated "tally sheets" to keep track of running totals for both enumeration districts and demographic traits.

   3In 1872, Chief Clerk of the Census Charles Seaton invented a simple machine that made tabulating census data easier by keeping the lines on large tallying sheets isolated and organized. The Census Office purchased Seaton's device and used it to finish the 1870 census. Seaton served as superintendent of the 1880 census, during which his device was used again.

   4Even with the Seaton device, the 1880 census took nearly the entire decade to tabulate and publish. Census data had become too extensive to be effectively counted by hand. Luckily, a technological advancement in data processing was on the horizon.

   1Following the 1880 census, the Census Bureau was collecting more data than it could tabulate. As a result, the agency held a competition in 1888 to find a more efficient method to process and tabulate data. Contestants were asked to process 1880 census data from four areas in St Louis, MO. Whoever captured and processed the data fastest would win a contract for the 1890 census.

   2Three contestants accepted the Census Bureau's challenge. The first two contestants captured the data in 144.5 hours and 100.5 hours. The third contestant, a former Census Bureau employee named Herman Hollerith, completed the data capture process in 72.5 hours.

   3Next, the contestants had to prove that their designs could prepare data for tabulation (i.e., by age category, race, gender, etc.). Two contestants required 44.5 hours and 55.5 hours. Hollerith astounded Census Bureau officials by completing the task in just 5.5 hours!

   4Herman Hollerith's impressive results earned him the contract to process and tabulate 1890 census data. Modified versions of his technology would continue to be used at the Census Bureau until replaced by computers in the 1950s.

   [...]

   5Herman Hollerith's tabulator consisted of electrically-operated components that captured and processed census data by "reading" holes on paper punch cards. The primary components of the system are explained below.

   6To begin tabulating data, census information had to be transferred from the census schedules to paper punch cards using gang punches and pantographs. Using this equipment, Census Bureau clerks "punched" each card to represent specific data on the census schedule.

   7Census Bureau clerks using pantographs could prepare approximately 500 cards per day. To operate the mechanism, the operator positioned the punching stylus over the desired hole in a punch card template. Each hole in the template corresponded to a specific demographic category. Pressing the stylus into the template created a punched hole in the paper card that was read by the Hollerith tabulator's card reader.

   8Each Hollerith tabulator was equipped with a card reading station. The manually-operated card reader consisted of two hinged plates operated by a lever (similar to a waffle iron). Clerks opened the reader and positioned a punched card between the plates. Upon closing the plates, spring-loaded metal pins in the upper plate passed through the punched data holes in the cards, through the bottom plate, and into wells of mercury beneath. Pins that passed through the punch card completed an electrical circuit when contacting the mercury below. The completed circuit energized the magnetic dials on the Hollerith tabulator and advanced the counting hands. Upon completion of the electrical circuit (signaled by the ringing of a bell), the clerk transcribed the data indicated by the dial hands.

   9The 1890 Hollerith tabulators consisted of 40 data-recording dials. Each dial represented a different data item collected during the census. The electrical impulses received as the reader's pins passed through the card into the mercury advanced the hands on the dials corresponding to the data contained on the punch card (i.e., responses to inquiries about race, gender, citizenship, age, etc). When the bell signaled the card had been read, the operator recorded the data on the dials, opened the card reader, removed the punch cards, and reset the dials.

   10A sorting table was positioned next to each tabulator. After registering the punch card data on the dials, the sorter specified which drawer the operator should place the card. The clerk opened the reader, placed the punch card in the designated sorter drawer, reset the dials, and positioned a new card to repeat the process.

   1Herman Hollerith, a former Census Office employee himself, invented a much more effective counting machine. His machine used specially encoded punch cards, each representing an individual's census data. The cards were fed into the counting machine, where the punched holes allowed metal pins to complete an electric circuit. When a circuit was completed, the dial for the corresponding trait would go up. Hollerith's device revolutionized census tabulation. The Census Office leased a fleet of the machines for the 1890 census count, which finished months ahead of schedule and far under budget. In 1896, Hollerith founded the Tabulating Machine Company. Almost twenty years later, after several mergers and management changes, this company became the International Business Machines (IBM) Corporation.

   2After Hollerith raised the rental prices for his machines to an intolerably high level for the 1900 census, the newly formed Census Bureau decided to create replacements in-house. Census Bureau employees, led by James Legrand Powers, developed a new electric tabulation machine. The new device, with an automatic feeder and card sorter, was an improvement over the machines that Hollerith was offering. In 1911, Powers, who held the patent for the machine that he had designed, left the Census Bureau to found the Powers Accounting Machine Company. Powers's enterprise was soon the most successful automatic tabulation company on the market; it later became part of the Remington Rand Corporation in 1927.

   1Few, who have not come directly in contact with a census office, can form any adequate idea of the labor involved in the compilation of a census of 50,000,000 persons, as was the case in the last census, or of over 62,000,000, as will be the case in the census to be taken in June, 1890. The fact, however, that Congress at its last session in “An Act to provide for the taking of the eleventh and subsequent censuses,” fixes the maximum cost of the next or eleventh census, exclusive of printing and engraving, at $6,400,000, will perhaps impress one with some idea of the magnitude of such an undertaking.

   [...]

   2To form some idea of the questions involved in the first plan, let us assume that the record relating to each person at the next census be written in a line across a strip of paper, and that such lines are exactly one-half inch apart, it would then take a strip of paper over 500 miles long to contain such records. These must be gone over, again and again, until all the desired combinations have been obtained. This is practically the method followed in compiling the tenth census. On the other hand, if written cards are to be used the prospect is hardly more encouraging. One hundred comparatively thin cards will form a stack over an inch high. In the next census, therefore, if such cards are to be used it will require a stack over ten miles high. Imagine for a moment the trouble and confusion which would be caused by a few such cards becoming misplaced. This method of individual cards was employed in the census of Massachusetts for 1885. The 2,000,000 cards there used weighed about 14 tons. Were the same cards to be used in the next United States census it would require about 450 tons of such cards.

   [...]

   3Two of the most important elements, in almost all statistical compilations, are “time” and “accuracy.” The rapidity with which results could be obtained with the present method, in a census, for example, would be dependent upon: 1st, the rate at which a clerk could punch the record-cards, and, 2d, the number of clerks employed upon this part of the work. The first can readily be determined by experiment, when the second becomes merely a simple arithmetical computation. The work of counting or tabulating on the machines can be so arranged that, within a few hours after the last card is punched, the first set of tables, including condensed grouping of all the leading statistical facts, would be complete. The rapidity with which subsequent tables could be published would depend merely upon the number of machines employed.

   4In regard to accuracy, it is apparent that the processes of counting and sorting, being purely mechanical, can be arranged, with such checks, that an error is practically impossible. The one possible source of error is in the punching of the cards. If proper precautions are here taken, a census practically free from errors of compilation could be obtained. Even in this respect the present method would have manifest advantages. A card wrongly punched could involve an error of only a single unit, while by all previous methods single errors involving an error in the result of tens, of hundreds, of thousands, or even more, are possible.

   1These three methods were now put to the test, four enumeration districts of the Census of 1880 in the city of St. Louis being taken. It was found that the time occupied in transcribing their contents by the Hollerith method was 72h. 27m.; by the Hunt method, 144h. 25m.; by the Pidgin method, 110h. 56m. The time occupied in tabulasing was found to be as follows: Hollerith’s electrical counters, 5h. 28m.; by the Hunt slips, 55h. 22m.; by the Pidgin chips, 44h. 41m. This settled it. The commission also estimated that on a basis of 65,000,000 population, the saving with the Hollerith apparatus would reach nearly $600,000. As a matter of fact, as the saving was based on an estimate of 500 cards punched per day, while 700 is the average, the saving is 40 per cent. more than was expected. It is needless to add that Mr. Hollerith’s invention was adopted, and that an arrangement was entered into by the Government with its inventor.

   2[...] The statement by Mr. Porter that the population of this great republic was only 62,622,250 sent into spasms of indignation a great many people who had made up their minds that the dignity of the republic could only be supported on a total of 75,000,000. Hence there was a howl, not of “deep-mouthed welcome,” but of frantic disappointment. And then the publication of the figures of New York! [...]

   3It is needless to say that in all this hurly-burly of discussion over the Census and its figures, the electrical counting system came in for its share of abuse. Just why it would not work was never made clearly apparent, for all that appeared in print derogatory to the mechanism merely went to prove its wonderful simplicity and inability to go wrong. [...]

   [...]

   4[...] The expertness acquired in manipulating the Hollerith machines may be inferred from the fact that some of the women tabulators thus counted as many as 50,000 persons a day, or the inhabitants of a good-sized city. The average for the women tabulators, who worked in the day time, was about 47,950 each; while the men tabulators, handicapped perhaps by coming on at night, averaged 32,935.

   5In this ingenious and expeditious manner, thanks to the Hollerith machines, the first, or “Dwelling House” count of the whole population of the United States as it stood on June 1, 1890, was made. Practically only six weeks were needed for the gigantic task. The announcements from the Census Office as to population of various sections followed each other rapidly, and a “rough count” for the whole country was ready as early as October 30, 1890. The last returns did not reach Mr. Porter until November 10, but he was able to issue his celebrated bulletin, giving the “official count” of 62,622,250, exactly a month later, namely, on December 12. Yet all the figures had been thoroughly checked; in reality, the people of the United States had been counted twice over. As Mr. Porter put it at a dinner given by the chiefs of the Census Office to celebrate the occasion, “For the first time in the history of the world, the count of the population of a great nation has been made by the aid of electricity” and every single one of our 62 millions “had marched as it were under the vision of the young men and women who had done such remarkable work with such extraordinary rapidity and precision.”

   Part 3: One event, four purposes. Work through the examples. Each one builds a short explanation for one purpose, then the fifth judges them against each other.

   • Cause and effect: why a new method was needed (Source 1, paragraphs 2 and 4; Source 4, paragraph 2)

     Explain why hand tallying could no longer keep up by 1890.

     Result: From 1850 the forms recorded information on individuals, so the tally sheets grew more complicated (Source 1, paragraph 2); even with the Seaton device, the 1880 census "took nearly the entire decade to tabulate and publish" (paragraph 4). As a result, the next count faced the same problem at a larger size. Hollerith adds pertinent data: one line per person on paper strips would run "over 500 miles," and cards like those of the 1885 Massachusetts census would weigh "about 450 tons" (Source 4, paragraph 2). The reasoning is sound, but the tons figure comes from the inventor making his case, so it should be cited as his estimate.

   • Chronological: the order of events, 1872-1911 (Sources 1, 3 and 5)

     Put the main events in order with their dates.

     Result: 1872: Seaton's device, first used for the 1870 census (Source 1, paragraph 3). 1880: a census that took nearly the decade to finish (paragraph 4). June 1, 1890: the population is counted "as it stood" on that day (Source 5, paragraph 5). 1896: Hollerith founds the Tabulating Machine Company (Source 3, paragraph 1). Next: he raises his rental prices for the 1900 census, so the newly formed Census Bureau builds its own machines, and in 1911 Powers leaves to found his company (Source 3, paragraph 2). A timeline like this is strong on order but says little about why each change happened.

   • Procedural: the steps a clerk followed (Source 2, paragraphs 6-10)

     Explain, as a set of steps, how one punched card moved through the system.

     Result: A clerk punched the card with a pantograph, one hole for each answer (paragraphs 6-7). At the tabulator, a clerk closed the card reader on the card, the dials advanced, and a bell signaled that the card had been read (paragraphs 8-9). The clerk recorded the dials, put the card in the drawer the sorter named, reset the dials and began the next card (paragraphs 9-10). The sorted drawers then fed the next round of counting, so the sequence is a loop, not a straight line: a non-linear sequence.

   • Technical: how the machine knew a hole was there (Source 2, paragraph 8)

     Explain the mechanism inside the card reader.

     Result: Spring-loaded pins in the upper plate pressed down on the card. Where there was a hole, a pin passed through "into wells of mercury beneath" and "completed an electrical circuit"; the current "energized the magnetic dials" and advanced the counting hands. Where there was no hole, the paper stopped the pin, so no circuit was closed and nothing was counted. The explanation is technical because it shows how the device works, not who used it or why it was chosen.

   • Strengths and weaknesses given purpose (Examples 1-4)

     Which of the four explanations best answers the question "Why did the Census Office change its methods?"

     Result: Only the cause-and-effect explanation answers why. The chronological one is strong for showing what came before what, but weak for a why question because it gives no links. The procedural and technical ones are strong for a new clerk or an engineer but weak for this question. A writer should name the purpose first, then judge every part against it.

3. Guided Practice15 minutes

   Groups of four use Diagram 1. Each member takes one purpose and writes a three-sentence explanation of the 1890 count for it, using a different source from the others. The group then answers: Which of our four explanations is strongest for a city official in 1891 who doubts the count, and why? Expect groups to see that the official needs cause and effect plus evidence about accuracy, which no single purpose supplies, and to notice that the critics' own words barely appear in these sources.

4. Independent Practice15 minutes

   Each student writes an explanation (eight to ten sentences) answering Why did the 1890 count go faster than the 1880 count? The student names the purpose first, uses at least one non-linear move (such as opening with the 1890 result and then going back to 1880), cites at least three pieces of significant data from at least two sources, and ends with two sentences: one strength and one weakness of the explanation given its purpose.

   Look-fors for the teacher: data that bear directly on speed rather than on cost alone; a sequence that stays true even when it is told out of order; at least one source whose stake is named; and a weakness that comes from the sources, such as the Bureau describing its own success.

5. Closure10 minutes

   Exit ticket: "Name the purpose of your explanation in one word. Then name one fact that would be essential for that purpose but out of place for a different one."

   Teacher note on the sources: Martin openly favored the machines, and the critics he answers appear only in the short phrases he quotes; the page has no source written by a critic or by a clerk. Students should treat his descriptions of the critics as one side's summary. His aside that the men tabulators were "handicapped perhaps" by night work is his guess, and his praise of women clerks elsewhere in the article reflects attitudes of 1891. Source 6, the second part of Martin's article, is printed with the homework.

   1In one of the newspaper articles appearing recently on the subject, two alleged samples of these complete cards were given in order to show that the “chances of error were largely increased by the mechanical devices employed,” while “there was small possibility of detection.” The funny part about the exposé in question is that both cards lacked the impress of the gang punch, and therefore were not part of the Census record at all. In other words, they were imperfect cards that had been thrown aside by the punchers themselves, and had not even reached the Hollerith electric machines, which would have been as prompt and unerring in their rejection as are bank tellers in casting out false coin. The present writer, while in Washington, asked specially as to imperfect records, and was taken into the little room where cards rejected by the machines were being set right by reference to the original schedules. A glance at the handful of men there, revising the work made by the handling of half a million cards daily, showed the percentage of wrong cards to be very small. [...]

   [...]

   2It is estimated that each of the machines thus compiles and registers information daily that would require the efforts of 20 clerks if sought by the old system of tally sheets. But that is not all. Added to the ability to secure special details, finer analysis, and the economy in time and labor, we have the greater accuracy. The machine automatically throws out any card that is wrong. Suppose, for instance, that age or sex has not been punched. Where there should be a hole for the plunger pin to go through, closing the circuit, the card is intact. The circuit is open, and the monitor bell just to the left of the press, refuses to give its cheery signal of correctness. It is then a very easy matter to refer back to the schedule stowed away in the old church across the street and fill up the deficiency by the paradoxical process of making a hole. [...]

   [...]

   3As a few figures were given of the records made with the punching machines, it may be worth while, in passing, to cite some that relate to the tabulation work. It has been stated that at the time of the writer’s visit to the Census Office, 81 clerks had handled 556,346 cards that day, an average of 6,868 each. [...]

   Quiz passage. Questions 13-16 of the quiz use Source 7, three invented student explanations. Each is deliberately weak, for students to judge and repair.

   1These three explanations were invented for this page. Each was written by an invented student, and each is deliberately weak in at least one way, so that students can judge and repair it.

   2Dana's procedural explanation, answering "How did a clerk count one person on an 1890 Hollerith tabulator?": First, the clerk placed the card in the drawer of the sorting table. Then the clerk closed the card reader, so the pins passed through the holes into the mercury. Next, the dials advanced and the bell rang. Finally, the clerk used the pantograph to punch the holes for that person's answers.

   3Eli's cause-and-effect explanation, answering "Why did the Census Office choose Hollerith's system for 1890?": The main cause is that Hollerith was a former Census Office employee, so officials already knew and trusted him. After he got the contract, the 1890 count finished months ahead of schedule, which proves that choosing a former employee was the right decision.

   4Farah's explanation, answering "Why did the 1890 count go faster than the 1880 count?": In 1872, Charles Seaton invented his device, and it was used for the 1870 and 1880 censuses. The 1880 census took nearly the entire decade to tabulate and publish. Next, three methods were tested on records from St. Louis. In 1890, Hollerith's machines were used. In 1900, Hollerith raised his rental prices.

Differentiation Strategies

Assessment Guidance

1. Question 1 of 20 · Multiple Choice

   A student's question is "How did a census clerk turn one person's answers into holes in a card?" Which purpose should the explanation have?

   ACause and effect: why it happened BChronological: the order of dates CProcedural: the steps a clerk took DTechnical: how the device works

2. Question 2 of 20 · Multiple Choice

   A student's question is "Why did the Census Bureau build its own tabulating machines in the 1900s?" Which purpose should the explanation have?

   ATechnical: how the device works BChronological: the order of dates CProcedural: the steps a clerk took DCause and effect: why it happened

3. Question 3 of 20 · Multiple Choice

   Which purpose does Source 1 mainly serve?

   ATechnical: how the Seaton device worked BProcedural: the steps a clerk followed CChronological: changes up to 1880 DCause and effect: why Hollerith won

4. Question 4 of 20 · Multiple Choice

   Source 5, paragraph 4, says the women tabulators averaged about 47,950 persons a day and the men 32,935. How many more persons a day did the women average?

   A15,015 more B15,025 more C80,885 more D150,150 more

5. Question 5 of 20 · Multiple Choice

   Martin says the men tabulators were "handicapped perhaps by coming on at night" (Source 5, paragraph 4). How should an explanation treat this phrase?

   AAs a measured fact, since he gives exact averages BAs a possible cause that he does not test CAs the Census Office's official finding DAs proof that night shifts slow all workers

6. Question 6 of 20 · Multiple Choice

   Martin says the official count came "exactly a month later" than November 10, on December 12 (Source 5, paragraph 5). What do the dates show?

   A30 days: exactly as he says B32 days: close, not exact C33 days: more than a month D42 days: far more than a month

7. Question 7 of 20 · Multiple Choice

   Martin says the critics had expected a total of 75,000,000, and the official count was 62,622,250 (Source 5, paragraphs 2 and 5). By about how much did the count fall short of what they expected?

   AAbout 1.2 million BAbout 12.4 million CAbout 13.4 million DAbout 137.6 million

8. Question 8 of 20 · Multiple Choice

   Why is Source 5 a weak source for explaining what the critics of the count believed?

   AIt was published several decades after the count BIt reports critics in a supporter's words CIt gives no numbers at all about 1890 DIt was written by the machine's inventor

9. Question 9 of 20 · Multiple Choice

   Source 3 says the 1890 count "finished months ahead of schedule and far under budget." What would make this claim significant data for a cause-and-effect explanation?

   ARepeating it in a second Census Bureau page BQuoting Porter's praise at the 1890 dinner CAdding the word "electric" to the sentence DPlanned and actual dates and costs

10. Question 10 of 20 · Multiple Choice

    Which statement is sound cause-and-effect reasoning that Source 3, paragraph 2, supports?

    ABecause the Bureau built its own machines, Hollerith raised his rental prices BBecause Powers left the Bureau in 1911, Hollerith raised his rental prices CBecause the 1890 count went well, the Bureau stopped using machines in 1900 DHollerith raised his prices, so the Bureau built its own machines

11. Question 11 of 20 · Multiple Choice

    Source 1, paragraph 2, says that in 1850 census forms began collecting information on individuals, and "as the census form became more complicated, tallying census results became increasingly difficult." What link does this sentence make?

    AMore detail for each person made the tallying harder BHarder tallying caused the forms to collect more detail CIndividual records made the census cheaper to count DThe Seaton device caused the forms to become complicated

12. Question 12 of 20 · Multiple Choice

    Which outline for an explanation of the 1890 count is non-linear but keeps every event in its true order?

    AOpen with 1890, then 1880, and say 1880 came after BList 1880, 1890 and 1900 in date order with no links COpen with the 1900 price rise, then return to the contest DOpen with 1900, then say that Hollerith's machines counted the 1880 census

13. Question 13 of 20 · Multiple Choice

    Read Dana's procedural explanation in Source 7, paragraph 2. What is its main problem?

    AIts steps are in the wrong order BIt does not use any source at all CIt answers a why question instead DIt gives far too many numbers

14. Question 14 of 20 · Multiple Choice

    Read Eli's cause-and-effect explanation in Source 7, paragraph 3. What is its main weakness?

    AIt puts the 1880 and 1890 censuses in the wrong order of time BIt uses a technical purpose for a procedural question CIts cause is unsupported, and it treats the result as proof DIt admits too many weaknesses for its cause-and-effect purpose

15. Question 15 of 20 · Multiple Choice

    Read Farah's explanation in Source 7, paragraph 4. Judged against its purpose, what is its main weakness?

    AIts dates do not match the sources BIt does not cite any of the sources CIt explains the circuit in too much detail DIt is a timeline, not a why

16. Question 16 of 20 · Short Answer

    Rewrite Farah's explanation (Source 7, paragraph 4) so that it fits its purpose. Keep her true dates, add at least two reasoning links, and cut anything that does not bear on the question.

    Show model answer

17. Question 17 of 20 · Short Answer

    Repair Eli's explanation (Source 7, paragraph 3). Replace his main cause with one the sources support, cite significant data, and end with one weakness of the repaired explanation given its purpose.

    Show model answer

18. Question 18 of 20 · Short Answer

    Hollerith wrote that one line per person, half an inch apart, would need a strip "over 500 miles long" for the 1890 census (Source 4, paragraph 2). How many people's records fit in 500 miles at half an inch each (1 mile = 63,360 inches)? What does your answer suggest about the population he assumed, and how should a writer use his figure?

    Show model answer

19. Question 19 of 20 · Short Answer

    Explain one strength and one weakness of Source 2 for a technical explanation of the card reader, and one strength and one weakness of Source 2 for a cause-and-effect explanation of why Hollerith won the contract.

    Show model answer

20. Question 20 of 20 · Short Answer

    Write a non-linear explanation (five to seven sentences) of how the 1890 count was produced and announced. Open with the December 12, 1890 bulletin, keep every date true, use at least two pieces of data, name your purpose, and end with one weakness.

    Show model answer

These standards connect to D4.2.9-12: prerequisites to review first, parallel standards at the same level, and next steps that build on it.

Standard text: National Council for the Social Studies (NCSS), The College, Career, and Civic Life (C3) Framework for Social Studies State Standards: Guidance for Enhancing the Rigor of K-12 Civics, Economics, Geography, and History (Silver Spring, MD: NCSS, 2013). NCSS was not involved in the production of this lesson and does not endorse it.