Spatial Correlation between Sex Ratio and Literacy Rate in Palakkad District, Kerala
Literacy rate is an important indicator of socio-economic development. By 2030, the United Nations Sustainable Development Goals include ensuring all youth and a substantial proportion of adults achieve literacy (United Nations, 2018). The 2011 Indian census defines literacy as, “a person aged seven and above who can both read and write with understanding in any language.” India has long struggled with increasing literacy rate; yet has made significant progress. From 43.6% in 1981, 52.2% in 1991, 64.8% in 2001, up to 74% in 2011.
A lot of attention has been placed on the southern state of Kerala which has historically outperformed other states. In 2011, Kerala was the most literate state with a rate of 93.91 (India Census, 2011). In 2013, the Athulyam scheme, aimed at providing primary schooling to ages 1 to 50. In 2016, the president and minister of education announced that Kerala had achieved 100% literacy. Although it is easy to contest the claim; the success of Kerala is beyond doubt.
Researchers have begun looking for variables that influence Kerala’s success. Several studies have demonstrated a correlation between sex ratio and literacy rates in the state of Kerala including Karrar (2014) and Jasim (2017). These researchers found the higher the sex ratio, the higher the literacy rate. Karrar (2014) found a correlation while focusing on aggregated district level 2011 census data. Jasim (2017) found a correlation focusing on the block level of the Thiruvananthapuram district.
India is ethnically, culturally, religiously, and linguistically diverse. Although a correlation between two variables is highly simplistic, sex ratio is a critically important variable in India, which has a history of selective sex abortions. Traditional and even modern cultural preference of sons has led to extreme disparity between the number of males to females. The 2011 census found 940 females per 1000 males, amounting to over 35 million more males than females (Ministry of Home Affairs, 2011). Therefore, if there is a link between sex ratio and literacy rate, a policy can be made that may be able to address both indicators.
Is there a correlation between sex ratio (number of females per 1000 males) and literacy rate? Sex ratio is the independent variable and literacy rate is the dependent variable. Hypothesis: There is no correlation between sex ratio and literacy rate.
This study will examine literacy and sex ratio in the Palakkad district of the South Indian state of Kerala. The state is divided into 14 districts. Each district is then divided into Taluks. Each Taluk comprises several CD Blocks. Each CD block consists several towns and villages. The unit of analysis is the CD block level.
This study replicates the methodology of Jasim (2017), who disaggregated district data and looked at the community development block (CD Block) level. Data came from the 2011 Indian Census. The census bureau provides spreadsheets of CD blocks and town/village data. Each spreadsheet contains a record total for the CD block, followed by the towns/villages in that CD block. Data was cleaned in preparation for use in ArcGIS and R Statistical software. Column headings were cleaned up, and town/village records were deleted from the spreadsheet leaving 13 CD blocks in the Palakkad district.
Pearson’s R correlation and Spearman’s ranked correlation tests were calculated in the R statistical software. Although both tests are used, the data breaks assumptions of the Pearson test, namely the assumption of outliers. Therefore, the Spearman’s rank is the primary measure of correlation. It is a nonparametric version of the Pearson’s correlation test which measures the strength and direction of two ranked paired samples.
Because land is a politically charged issue in India, the government does not provide open access to CD block or town/village boundaries. In this study, to define CD block boundaries, polygons were digitized in ArcGIS based on several maps of the Palakkad district CD blocks. The CD blocks in this study are not meant to visualize political boundaries, only to roughly visualize the spatial patterns of sex ratio and literacy rate. Census data was joined with the newly created cd block boundary attribute table. Data is visualized using a graduated color scheme with five natural break classes.
Per the 2011 census, the Palakkad district has a population of 2,810,890. Based on the census bureau definition of literacy as, “a person aged seven and above who can both read and write with understanding in any language,” According to the 2011 census (see Table 1), all CD Blocks in Palakkad had literacy rates higher than the national average. The total literacy rate in Palakkad is 88.49%, the lowest in Kerala. CD blocks, Pattabi (93.67), Sreekrishnapuram (93.34), Ottappalam (92.98), and Thrithala (92.52) have the highest literacy in the district. These CD Blocks are all in the western Taluk of Ottappalam. Among the lowest literacy rate in the district are the southeastern CD blocks. The lowest literacy rate in the district is Attapadi (75.07) in the north.
According to the 2011 census, sex ratio is the number of females per 1000 males. The Palakkad district is ranked 10th out of 14 districts in Kerala for sex ratio, having 1067 females for every 1000 males. Much higher than the national average of 940. According to the 2011 census, all CD Blocks in Palakkad had a higher sex ratio than the national average. The highest sex ratio in the district is Thrithala (1122.43), Ottappalam (1105.41), Sreekrishnapuram (1091.38), and Pattambi (1090.85). These CD Blocks are all in the western Taluk of Ottappalam. The lowest sex ratio in the district is in the southeastern CD Blocks. The lowest sex ratio is in the northern CD Block of Attappady (1007.74).
The Pearson’s correlation test found evidence to reject the null hypothesis. The test found a statistically significant correlation between literacy rate and sex ratio of 0.8994409, F value = 46.59 (1 and 11 degrees of freedom), p-value=2.855e-5, 95% confidence interval of 0.69 to 0.97. A residual vs. leverage test was conducted to discover outliers which would have high leverage on the regression. Based on cooks’ distance, Attappady has a cooks’ distance of almost one, and Thrithala has a cooks distance of almost 0.5. Both CD Blocks should be considered outliers. Thrithala has a high sex ratio (1122.43), and Attappady has a low literacy rate (75.07). These factors contribute to the outlier status of each. For this reason, the Spearman's ranked correlation is a better test to measure data of this type.
The Spearman’s ranked correlation was conducted to confirm the Pearson test. Spearman’s ranked correlation is a nonparametric statistic which controls for outliers by ranking the data before calculating the regression. The Spearman test found a correlation of 0.91010989, F value = 46.59 (1 and 11 degrees of freedom), P-value=2.2e-16, 95% confidence interval of 0.69 to 0.97. Therefore, it can be concluded that there is a strong correlation between sex ratio and literacy rate in the Palakkad district of Kerala.
The results from this study demonstrate that more research about literacy and sex ratio in India. Karrar (2014) found evidence there is a correlation at the district level in Kerala, while Jasim (2017) found evidence of a correlation at the block level of the Thiruvananthapuram district. This research adds to the mounting evidence that something is going on in Kerala that needs to be better understood. The success of Kerala in moving the needle for both of these indicators and that there is a spatial correlation indicates there is a need for more in depth research to inform policy makers.
India Census. (2011). State of Literacy. Retrieved from http://censusindia.gov.in/2011-prov-results/data_files/india/Final_PPT_2011_chapter6.pdf
Jasim, H. (2017). Correlation between literacy rate and sex ratio in Thiruvananthapuram district: A geographical Study. International Journal of Applied and Pure Science and Agriculture.
Karrar, H.-e. (2014). A study of demographic characteristics in Kerala. Scholarly Research Journal for Humanity Science & English Language, 1(5).
Ministry of Home Affairs. (2011). Gender Composition. Retrieved from http://censusindia.gov.in/2011-prov-results/data_files/mp/06Gender%20Composition.pdf
United Nations. (2018). Goal 4: Quality Education. Retrieved from United Nations: https://www.un.org/sustainabledevelopment/education/