66. Given the characteristics of the population and housing censuses, and in particular the huge amount of information to be collected, processed and disseminated, the adoption of appropriate technology is one of the keys of the success of the census, regardless of the census methodology adopted.

67. From one census round to the next, developments in technology may change the way censuses are conducted. And the other way round: as long as methodological approaches evolve, technological developments often provide new solutions aimed at improving the efficiency of census operations.

68. Some decades ago, when the censuses were conducted in most countries with full field data collection using paper questionnaires, scanning technologies were developed to replace manual data capture. Since then, significant technological developments include the use of digital maps and geographical information system (GIS) technologies to supersede traditional census cartography, the use of the internet to provide respondents with an opportunity to submit their census information online, the use of tablets and other mobile devices for field staff to collect census information and manage field operations. All these innovations allowed countries to collect, transfer and process census data electronically, replacing in most countries paper questionnaires and documentation, with significant savings in terms of costs and time.

69. This chapter reports on several aspects of the technological practices adopted for the management of census operations in the 2020 round, focusing on changes from the 2010 round, online response, use of electronic devices in fieldwork, and software.

70. Six countries (Azerbaijan, Bulgaria, Canada, Slovakia, Tajikistan, Türkiye) did not use technology in significantly differently way in the 2020 census round compared to the previous census. Further five countries who conducted at least some direct enumeration (out of 31 such countries) did not answer this question.

71. The 21 countries reporting significant technology changes in the 2020 round mentioned different aspects. For 19 countries the technological change was related to the enumeration process: start or expansion of the internet response (11 countries), use of electronic devices (10 countries) and moving away from paper (5 countries: Georgia, Hungary, Italy, Republic of Moldova, Serbia).

72. Countries that mentioned the online response as a significant technology change in this round include Belarus, Czechia, Georgia, Kazakhstan, North Macedonia, the Russian Federation and the United States. Transition to the “online first” approach was highlighted by Germany, Luxembourg and Switzerland.

73. The changes related to electronic devices concerned the use of smartphones for fieldwork response collection (Czechia, Italy, Portugal, United States) and the introduction of computers or tablets for personal interviews (Belarus, Georgia, Kazakhstan, North Macedonia, Republic of Moldova and the Russian Federation).

74. Significant software-related changes pertained to the smartphone apps for data collection (Portugal, United States), communication platform for enumerators (Luxembourg), new optical character recognition software (Luxembourg) and data perturbation and geographical information management (Norway).

75. The United States highlighted the transition to the use of cloud computing as their new aspect of technology use. Cyprus, North Macedonia and the United Kingdom pointed out changes in the organization of data flows in the census process. Transition from personal to telephone interviews took place in Armenia.

76. Considering all reporting countries that conducted a field enumeration or a combined census in the 2020 round, the large majority (26 out of 32, that is 81%) provided an online response option to the respondents (Table 14). This is a significant increase compared to the 2010 round, when it was provided by only 18 countries (45%).

77. The online response option was more likely to be offered in countries with a field enumeration census (13 out of 15, that is 87%) than in countries with a combined census (13 out of 17, that is 76%).

	Total (out of 32 countries)	Type of census
		Field enumeration (15 countries)	Combined (17 countries)
Online response offered	26	13	13
Online response NOT offered	6	2	4

78. Among the 26 countries that provided an online response option, in 22 countries (85%) that was the main response channel, under an “internet first” approach. In the remaining countries, the internet response was one option among other possibilities (e.g. paper form, telephone, face-to-face), or there were different approaches for different parts of the country or specific population groups.

79. Among the countries that offered the online response option to most of their population, take-up varied from 15% of the respondents in Tajikistan to 96% in Portugal (Table 15). In 11 countries, more than half of the population responded over the Internet. In the previous census round, only three countries reached that level. In Switzerland the information was primarily drawn from registers, and only 2% of the population was enumerated online.

Field enumeration census		Combined census
Country	Percentage	Combined census	Percentage
Portugal	96	Slovakia	85
United Kingdom	89	Czechia	79
Canada	84	Hungary	69
Greece	67	Poland	53
France	60	Luxembourg	48
Malta	55	Israel	30
United States	52	Belarus	22
Kazakhstan	43	North Macedonia	20
Croatia	40	Switzerland	2
Russian Federation	16
Tajikistan	15

80. Most countries that used the online response option (17 out of 26, that is 65%) collected their data the same way from the entire population. The countries that collected the data differently for some population groups were each having a unique way of doing it. The practices included providing the paper-first option for older people (Switzerland), providing paper forms for the overseas population (France) or persons living in collective households (Luxembourg), conducting only face-to-face interviews with a specific population group (Israel), using administrative sources for a specific population group (Georgia), hand-delivery of questionnaires in areas of limited coverage by the postal service (United States) and the provision of the online option for diplomats only (Serbia).

81. In 23 of the 26 countries (88%), online forms were available for both personal computers and for tablets or smartphones. France and North Macedonia offered online forms only for personal computers, while Tajikistan offered a downloadable form to be completed by respondents offline.

82. Most countries (21 out of 26) that offered the online response option provided unique access codes to ensure security and privacy. Seventeen (17) countries integrated a form timeout after a specified period. Encryption was used by 10 countries, a personal identification number that allows exit and return by 6 countries and the Captcha method by 3 countries.

83. The ways of delivering the logins and passwords for secure access to the online form have become more diverse in the 2020 census round. Georgia, Israel, Kazakhstan, the United Kingdom and the United States used three different methods each. Further eight countries used two methods.

84. Sending a paper form to the respondent’s physical (mailing) address was the most popular method used by nine countries, including Italy, Luxembourg and Switzerland where this was the only method used. In six countries, enumerators distributed the access credentials door-to-door. In Portugal, this was the only method used.

85. Eight countries were able to rely on existing access systems, such as government services, banks or electronic id, and seven countries used multi-factor authentication methods. The United States offered an option for the online response without identification and login credentials.

86. Nearly all countries that offered the online response used drop-down menus (25 countries), automatic sequencing of questions in the online form (22) and assisted coding (search as you type, 20 countries). Interactive editing was also frequently used: in the hard form, preventing user from proceeding with unreconciled entries, in 16 countries, and in the soft form, permitting to proceed with unreconciled entries, in 15 countries. Fourteen (14) countries used an address register to complete or verify the address.

87. Twenty-six (26) countries collected data in the field using electronic questionnaires on laptops, tablets, smartphones or similar small devices (Table 16). Seven (7) countries used more than one type of device. In most countries, the number of smaller devices used (tablet or smartphone) is significantly higher compared to the number of large devices (laptop or tablet, respectively). Five (5) countries (Azerbaijan, Bulgaria, Canada, Luxembourg and Switzerland) conducted field enumeration without using electronic devices.

	Total (out of 32 countries)	Type of census
		Field enumeration (15 countries)	Combined (17 countries)
Electronic devices were used for data collection, including…	26	11	15
Laptop computers	12	5	7
Tablet computers	18	10	8
Smartphones (or similar small devices)	7	3	4
Electronic devices were NOT used	5	3	2

88. The use of devices by field staff, either for the purpose of recording actual census information or for management support, increased in the 2020 round; only ten countries used such technology in the field in the 2010 round and two countries in the 2000 round.

89. The use of electronic questionnaire on the handheld devices for the census data collection allows to improve data quality and processing speed due to the automated control of primary data, the rapid uploading of collected data to the data processing centres, monitoring of the field work by the GPS module of the device and other capabilities provided by the devices. Some countries used a text messaging facility to receive the information from respondents or to exchange information between field staff and census headquarters.

90. In 19 out of the 23 countries that used electronic devices in the field enumeration, the devices were purchased by the national statistical office (NSO). In Belarus, Estonia and Tajikistan, the NSO borrowed a part of the devices and in the United States, all of them. In four counties (Belarus, Georgia, Republic of Moldova and Tajikistan), a part of the devices were donated to the NSO. In Kyrgyzstan, Luxembourg and Portugal, enumerators used their own device. In Czechia and Israel, the work was outsourced and the contractor purchased the devices. In Germany, those federal states that used mobile devices in their enumeration purchased them.

91. Out of the 23 NSOs that used electronic devices in field enumeration, 16 (Armenia, Belarus, Cyprus, Estonia, Georgia, Hungary, Ireland, Italy, Kazakhstan, North Macedonia, Poland, Portugal, Russian Federation, Serbia, Tajikistan, United Kingdom) kept them for other projects. In 13 countries (Belarus, Croatia, Germany, Georgia, Hungary, Kazakhstan, North Macedonia, Republic of Moldova, Russian Federation, Serbia, Slovakia, Tajikistan, United Kingdom), the NSO donated some or all the devices to other government organizations or to charity. Four (4) countries returned the borrowed devices to their owners (Belarus, Portugal, Tajikistan, United States). In Ireland, a part of the devices were destroyed; in Czechia and in Israel, the devices were the contractor’s property.

92. The widespread use of devices in the census obviously creates some technical challenges. According to the survey results, the difficulties reported by most countries are related to the use of tablets during field operations. The most problematic were battery life limitations, reliability of data transmission, low GPS accuracy, poor mobile signal reception, difficulties with user training and weak or slow technical support. Some countries that used tablets experienced problems such as loss of devices, limited storage capacity, screen size or screen visibility. The same difficulties were mentioned by countries using smartphones and similar small devices. Laptop users had the least number of difficulties. For example, problems such as storage capacity and screen visibility are not typical for laptops. It was also noted that problems arise if the development and technical support of applications for devices was distributed among different teams.

93. Out of the 32 reporting countries with direct field enumeration, 29 mentioned using at least one international or national cyber security standard in their census. National government cyber standards were used by 16 countries, International Organization for Standardization (ISO) 27000 standards by 14 countries, and National Institute of Standards and Technology (NIST) by 6 countries.

94. Nine (9) countries used optical recognition software (OMR, OCR or ICR), out of the 15 countries that used paper questionnaires. Twelve (12) countries with direct field enumeration did not answer this question. While optical recognition techniques have been recommended in the 2010 and 2020 CES Recommendations, the usage of these techniques has become limited to few countries as such techniques are not necessary when data are collected with electronic devices, online or from administrative sources.

95. In total, 27 countries provided information on the type of software they used in different census operations (Table 17). In managing the field enumeration, 26 countries used their own, open source or custom-made software. Only four countries (Israel, Serbia, Slovakia and the United Kingdom) used commercial solutions, all in combination with other types of software.

96. For most census operations, own solutions prevail over commercial solutions. The use of commercial software remained limited to 4 to 8 countries in each of the following census operations: coding, editing and imputation, tabulation, record linkage, recruitment, logistics, training, dissemination, and communication and outreach. In about half of the cases where commercial software was used, another type of software (own, open source or custom-made) was also used for the same census operation.

97. By contrast, for data storage and geographic information systems, the role of commercial software was much more important. Thirteen (13) countries used commercial software for data storage and nine of them did not indicate the use of any other type of software for this purpose. For geographic information systems, 16 countries used commercial software and 7 of them did not indicate any other type.

Type of software applications and source	Total (out of 27 countries)	Type of census
		Field enumeration (11 countries)	Combined (16 countries)
FIELD PROCESS MANAGEMENT	26	10	16
Own	15	7	8
Open source	2	0	2
Commercial	4	1	3
Custom-made	11	5	6
DATA STORAGE	27	11	16
Own	12	7	5
Open source	4	2	2
Commercial	13	4	9
Custom-made	4	1	3
Transformation of administrative data into statistical data	24	10	14
Own	13	6	7
Open source	5	1	4
Commercial	5	1	4
Custom-made	6	4	2
CODING/EDITING AND IMPUTATION…	25	11	14
Own	12	6	6
Open source	7	3	4
Commercial	6	2	4
Custom-made	10	5	5
TABULATION	21	10	11
Own	12	5	7
Open source	2	2	0
Commercial	5	2	3
Custom-made	7	5	2
RECORD LINKAGE	24	10	14
Own	12	4	8
Open source	5	2	3
Commercial	5	1	4
Custom-made	6	4	2

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Type of software applications	Total (out of 33 countries)	Type of census
		Field enumeration (16 countries)	Combined (17 countries)
RECRUITMENT	18	10	8
Own	10	6	4
Open source	1	1	0
Commercial	6	2	4
Custom-made	7	5	2
LOGISTICS	23	10	13
Own	15	5	10
Open source	2	1	1
Commercial	6	3	3
Custom-made	6	5	1
GIS	23	8	15
Own	6	2	4
Open source	7	4	3
Commercial	14	4	10
Custom-made	7	4	3
TraINING	22	8	14
Own	14	6	8
Open source	3	1	2
Commercial	3	0	3
Custom-made	8	3	5
DISSEMINATION	24	10	14
Own	16	7	9
Open source	4	2	2
Commercial	5	1	4
Custom-made	8	4	4
COMMUNICATION, OUTREACH	19	9	10
Own	13	6	7
Open source	2	1	1
Commercial	4	1	3
Custom-made	7	5	2

98. Out of the 32 reporting countries with direct field enumeration, 24 (75%) used technology to enhance accessibility. Seventeen (17) countries made technological provisions for better visual accessibility of the census questionnaire, considering issues such as font size and colour. Thirteen (13) countries recognised cognitive issues such as the use of simple language. Physical accessibility was mentioned by 8, speech by 6 and auditory accessibility by 5 countries.

99. Thirty-two (32) countries provided information on the use of cloud technologies. Thirteen (13) of them answered that they did not use the cloud for any aspects of the census. Of the 19 countries who did, 12 used it for online survey collection and 8 for processing. The use of cloud technologies is less common for field management (5 countries), field recruitment (4), logistics (4) and dissemination (3 countries). Mobile device management and machine learning are additionally indicated as new fields.

100. Out of the 29 countries who provided information on anonymisation techniques, nearly half, 13, indicated the use of data pseudonymisation. For 6 countries, this was the only anonymisation technique applied. Data generalisation was used by 8 countries and static data masking by 6 countries. Other methods were also applied, such as data perturbation (5 countries), data swapping (5), rounding of values (4), synthetic data (2) and dynamic data masking (1 country). It would be beneficial to harmonise the use of anonymisation techniques, for example, using API-based secure processing with standardized methods to avoid methodological differences.

101. Many of those countries that carried out field operations to collect all or part of their census information reported a variety of other technological aids for doing so. Geographic information systems (GIS) – now pretty well established globally – were utilized for the purposes of mapping by more countries (19 of those that responded to the survey) than any other technological tool. Of these, 13 countries reported using such technology for the first time in their field operation. However, just as many countries reported that they did not use GIS at all, relying, presumably, on more traditional cartographic methods for mapping.