# List of packages
packages <- c("tidyverse", "infer", "broom", "fst", "modelsummary", "effects", "survey", "interactions") # add any you need here

# Install packages if they aren't installed already
new_packages <- packages[!(packages %in% installed.packages()[,"Package"])]
if(length(new_packages)) install.packages(new_packages)

# Load the packages
lapply(packages, library, character.only = TRUE)
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Task 1

Graph the histogram distribution using the populist scale (as we did in the tutorial) for the country of Sweden. What do you note?

sweden_data <- read.fst("sweden_data.fst")
sweden_data$trstplt <- ifelse(sweden_data$trstplt > 10, NA, sweden_data$trstplt)
sweden_data$trstprl <- ifelse(sweden_data$trstprl > 10, NA, sweden_data$trstprl)
sweden_data$trstprt <- ifelse(sweden_data$trstprt > 10, NA, sweden_data$trstprt)


sweden_data$trust <- scales::rescale(sweden_data$trstplt + sweden_data$trstprl + sweden_data$trstprt, na.rm = TRUE, to = c(0, 100))

sweden_data$populist <- scales::rescale(sweden_data$trust, na.rm = TRUE, to=c(100,0))
ggplot(sweden_data, aes(x = populist)) +
  geom_histogram(bins = 30, fill = "blue", color = "black") +
  theme_minimal() +
  labs(title = "Distribution of Populist Scale for Sweden",
       x = "Populist Scale",
       y = "Count")
## Warning: Removed 2503 rows containing non-finite values (`stat_bin()`).

Based on this histogram, I can note that it illustrates a normal distribution. Most of the data falls within the middle percentile, with a large peak at around 50% on the populist scale. Therefore, on average Swedish people idenitfy as populists to a moderate degree. ## Task 2

Run a linear regression with populist attitudes as the outcome, educational attainment (recoded as a binary “BA or more” and “No BA”), and using the Swedish data. Print the intercept and coefficients only and interpret. Then do a tidy model table displaying the p-value (with digits = 3) and interpret.

table(sweden_data$edulvlb)
## 
##    0  113  213  313  321  323  413  423  520  610  620  710  720  800 5555 7777 
##  144  812 1214  944 1144 1144  325  893 1008  746  573  472  834  137   73    8 
## 8888 9999 
##   14   27
sweden_data <- sweden_data %>%
  mutate(
    ID = case_when(
      edulvla %in% 0:4 ~ "BA or more",                    
      edulvla %in% 5:10 ~ "BA or more",                   
      edulvla %in% c(55, 77, 88, 5555, 7777, 8888, 9999) ~ NA_character_ ,    
      TRUE ~  "No BA"                          
    )
  )


table(sweden_data$ID)
## 
## BA or more      No BA 
##       7679      10524
sweden_pop_model <- lm(populist ~ ID, data = sweden_data)
coefficients_sweden <- coef(sweden_pop_model)
print(coefficients_sweden)
## (Intercept)     IDNo BA 
##    51.35224    -3.23235

Intercept (51.35):

IDRight Coefficient (-3.23235):

tidy(sweden_pop_model)
## # A tibble: 2 × 5
##   term        estimate std.error statistic  p.value
##   <chr>          <dbl>     <dbl>     <dbl>    <dbl>
## 1 (Intercept)    51.4      0.266    193.   0       
## 2 IDNo BA        -3.23     0.330     -9.80 1.29e-22
tidy(sweden_pop_model) |>
knitr::kable(digits = 3)
term estimate std.error statistic p.value
(Intercept) 51.352 0.266 192.854 0
IDNo BA -3.232 0.330 -9.802 0
summary(sweden_pop_model)
## 
## Call:
## lm(formula = populist ~ ID, data = sweden_data)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -51.352 -14.787  -1.453  11.981  51.880 
## 
## Coefficients:
##             Estimate Std. Error t value Pr(>|t|)    
## (Intercept)  51.3522     0.2663 192.854   <2e-16 ***
## IDNo BA      -3.2323     0.3298  -9.802   <2e-16 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 19.68 on 15700 degrees of freedom
##   (2514 observations deleted due to missingness)
## Multiple R-squared:  0.006082,   Adjusted R-squared:  0.006019 
## F-statistic: 96.07 on 1 and 15700 DF,  p-value: < 2.2e-16

In both cases, p-value indicates it is statistically significant and that the null hypothesis is rejected.

Task 3

Now using the Italian dataset and the authoritarian values scale (as we did in the tutorial), graph the average by survey year. Interpret.

italy_data <- read.fst("italy_data.fst")
italy_data <- read.fst("italy_data.fst")
## Creates an authoritarian values scale based on human modules items (can also do libertarian value scale)
italy_data <- italy_data %>%
  mutate(behave = ipbhprp,
         secure = impsafe,
         safety = ipstrgv,
         tradition = imptrad,
         rules = ipfrule) %>%
  mutate(across(c("behave", "secure", "safety", "tradition", "rules"),
                ~ na_if(.x, 7) %>% na_if(8) %>% na_if(9))) %>%
  # Apply the reverse coding
  mutate(across(c("behave", "secure", "safety", "tradition", "rules"), ~ 7 - .x ))

# Now you can calculate 'schwartzauth' after the NA recoding
italy_data$auth <- scales::rescale(italy_data$behave + 
                      italy_data$secure + 
                      italy_data$safety + 
                      italy_data$tradition + 
                      italy_data$rules, to=c(0,100), na.rm=TRUE)


italy_data <- italy_data %>% filter(!is.na(auth))
table(italy_data$secure)
## 
##    1    2    3    4    5    6 
##   54  139  626 1856 2876 2881
table(italy_data$auth)
## 
##   0  12  16  20  24  28  32  36  40  44  48  52  56  60  64  68  72  76  80  84 
##   7   4   4   9  13  20  27  57 113 155 163 323 367 596 647 789 823 897 992 733 
##  88  92  96 100 
## 632 465 299 297
ggplot(italy_data, aes(x = auth)) +
  geom_histogram(bins = 30, fill = "blue", color = "black") +
  theme_minimal() +
  labs(title = "Distribution of Authoritarian Scale for Italy",
       x = "Authoritarian Scale",
       y = "Count")

italy_data$year <- NA
replacements <- c(2002, 2004, 2006, 2008, 2010, 2012, 2014, 2016, 2018, 2020)
for(i in 1:10){
  italy_data$year[italy_data$essround == i] <- replacements[i]
}
auth_avg <- italy_data %>%
  group_by(year) %>%
  summarize(auth_avg = mean(auth, na.rm = TRUE))

plot_auth <- ggplot(auth_avg, aes(x = year, y = auth_avg)) +
  geom_point(aes(color = auth_avg), alpha = 1.0) + 
  geom_line(aes(group = 1), color = "blue", linetype = "dashed") +  
  labs(title = "Authoritarian Scale Average by Year (Italy)",
       x = "Survey Year",
       y = "Authoritarian Scale Average") +
  theme_minimal() +
  theme(legend.position = "none") +
  scale_y_continuous(limits = c(0, 100))

print(plot_auth)

The yearly avergae for authoritarian values of Italians has remained consistent at around 75%. This indicates that on average, Italians have authoritarian tendencies given that they continue to score close to 75% on the authoritarian value scale.

Task 4

Now run a linear regression model, using the modelsummary package, with authoritarian values as the outcome, and generations as the predictor/potential explanatory variable, and using the Italian data again. Rename the coefficients using the coef_rename function. Interpret the coefficients, whether they are statistically significant, and the adjusted R-squared.

model_data <- italy_data %>%
  mutate(
    # Recoding gender
    gndr = case_when(
      gndr == 1 ~ "Male",
      gndr == 2 ~ "Female",
      gndr == 9 ~ NA_character_,
      TRUE ~ as.character(gndr)
    ),

 # Recoding education
    educ.ba = case_when(
      essround < 5 & edulvla == 5 ~ "BA or more",
      essround >= 5 & edulvlb > 600 ~ "BA or more",
      TRUE ~ "No BA"
    ),
    
    # Handle NAs for education levels
    edulvla = ifelse(edulvla %in% c(77, 88, 99), NA_integer_, edulvla),
    edulvlb = ifelse(edulvlb %in% c(5555, 7777, 8888), NA_integer_, edulvlb),
    
    # Explicitly making 'No BA' the reference category
    educ.ba = factor(educ.ba, levels = c("No BA", "BA or more")),

    # Recoding age, setting 999 to NA
    age = ifelse(agea == 999, NA, agea),

    # Recoding cohort variable, setting years before 1930 and after 2000 to NA
    cohort = ifelse(yrbrn < 1930 | yrbrn > 2000, NA, yrbrn),

    # Recoding generational cohorts based on year of birth
    gen = case_when(
      yrbrn %in% 1900:1945 ~ "1",
      yrbrn %in% 1946:1964 ~ "2",
      yrbrn %in% 1965:1979 ~ "3",
      yrbrn %in% 1980:1996 ~ "4",
      TRUE ~ as.character(cohort)  # Keeping other values as character if they do not fit the ranges
    ),

    # Converting cohort to a factor with labels
    gen = factor(gen,
                 levels = c("1", "2", "3", "4"),
                 labels = c("Interwar", "Baby Boomers", "Gen X", "Millennials"))
  )
table(model_data$gen)
## 
##     Interwar Baby Boomers        Gen X  Millennials 
##         1026         2580         2214         1811
model1 <- lm(auth ~ gen, data = model_data)
model2 <- lm(auth ~ gndr, data = model_data)
model3 <- lm(auth ~ educ.ba, data = model_data)
modelsummary(
  list(model1),
  fmt = 1,
  estimate  = c( "{estimate} ({std.error}){stars}"),
  statistic = NULL,
  coef_omit = "Intercept")
 (1)
genBaby Boomers −1.1 (0.6)*
genGen X −2.1 (0.6)***
genMillennials −3.6 (0.6)***
Num.Obs. 7631
R2 0.006
R2 Adj. 0.006
AIC 62934.0
BIC 62968.7
Log.Lik. −31462.009
RMSE 14.94

Coefficients Interpretation:

Adjusted R-Squared (Adj. R² = 0.006):

The adjusted R-squared value of 0.006 means that the ‘gen’ variable explain approximately 0.6% of the variance in the authoritarian values scale for Italy, after accounting for the number of predictors. While statistically significant, this suggests that the model explains only a small portion of the variability in authoritarian values, pointing to other factors outside generational differences that may play critical roles in shaping these attitudes. ## Task 5

Now visualize, using the modelplot() function from the modelsummary package, coefficient estimates and 95% confidence intervals for the following three models:

Model 1 = populist attitudes scale as the outcome; left/right as the single predictor (omitting moderates as we did in the tutorial), and using data for Greece.

Model 2 = populist attitudes scale as the outcome; gender as the single predictor, and using data for Greece.

Model 3 = populist attitudes scale as the outcome; generations as the single predictor (using the four generational category recode we did in the tutorial), and using data for Greece. Interpret.

greece_data <- read.fst("greece_data.fst")
greece_data <- read.fst("greece_data.fst")



greece_data$trstplt <- ifelse(greece_data$trstplt > 10, NA, greece_data$trstplt)
greece_data$trstprl <- ifelse(greece_data$trstprl > 10, NA, greece_data$trstprl)
greece_data$trstprt <- ifelse(greece_data$trstprt > 10, NA, greece_data$trstprt)


greece_data$trust <- scales::rescale(greece_data$trstplt + greece_data$trstprl + greece_data$trstprt, na.rm = TRUE, to = c(0, 100))


greece_data$populist <- scales::rescale(greece_data$trust, na.rm = TRUE, to=c(100,0))
ggplot(greece_data, aes(x = populist)) +
  geom_histogram(bins = 30, fill = "blue", color = "black") +
  theme_minimal() +
  labs(title = "Distribution of Populist Scale for Greece",
       x = "Populist Scale",
       y = "Count")
## Warning: Removed 2735 rows containing non-finite values (`stat_bin()`).

table(greece_data$edulvlb)
## 
##    0  113  213  229  313  321  323  421  520  610  620  710  720  800 5555 7777 
##  251  837  576   30 1785  142  255  312   67  167  871   25  164   14    7    9 
## 8888 
##    2
greece_data <- greece_data %>%

  mutate(
    ID = case_when(
      lrscale %in% 0:4 ~ "Left",                    
      lrscale %in% 6:10 ~ "Right",                   
      lrscale %in% c(77, 88, 99) ~ NA_character_,   
      TRUE ~ NA_character_                          
    )
  )
table(greece_data$ID)
## 
##  Left Right 
##  2688  3522
greece_pop_model <- lm(populist ~ ID, data = greece_data)
coefficients_greece <- coef(greece_pop_model)
print(coefficients_greece)
## (Intercept)     IDRight 
##   72.002115   -8.799429
tidy(greece_pop_model)
## # A tibble: 2 × 5
##   term        estimate std.error statistic  p.value
##   <chr>          <dbl>     <dbl>     <dbl>    <dbl>
## 1 (Intercept)    72.0      0.478     151.  0       
## 2 IDRight        -8.80     0.643     -13.7 6.33e-42
tidy(greece_pop_model) |>
knitr::kable(digits = 3)
term estimate std.error statistic p.value
(Intercept) 72.002 0.478 150.677 0
IDRight -8.799 0.643 -13.695 0
summary(greece_pop_model)
## 
## Call:
## lm(formula = populist ~ ID, data = greece_data)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -72.002 -16.536   1.331  17.998  36.797 
## 
## Coefficients:
##             Estimate Std. Error t value Pr(>|t|)    
## (Intercept)  72.0021     0.4779   150.7   <2e-16 ***
## IDRight      -8.7994     0.6425   -13.7   <2e-16 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 22.44 on 4934 degrees of freedom
##   (7622 observations deleted due to missingness)
## Multiple R-squared:  0.03662,    Adjusted R-squared:  0.03642 
## F-statistic: 187.5 on 1 and 4934 DF,  p-value: < 2.2e-16
model_data <- greece_data %>%
  mutate(
    # Recoding gender
    gndr = case_when(
      gndr == 1 ~ "Male",
      gndr == 2 ~ "Female",
      gndr == 9 ~ NA_character_,
      TRUE ~ as.character(gndr)
    ),

    educ.ba = case_when(
      essround < 5 & edulvla == 5 ~ "BA or more",
      essround >= 5 & edulvlb > 600 ~ "BA or more",
      TRUE ~ "No BA"
    ),
    

    edulvla = ifelse(edulvla %in% c(77, 88, 99), NA_integer_, edulvla),
    edulvlb = ifelse(edulvlb %in% c(5555, 7777, 8888), NA_integer_, edulvlb),
    
 
    educ.ba = factor(educ.ba, levels = c("No BA", "BA or more")),

  
    age = ifelse(agea == 999, NA, agea),

   
    cohort = ifelse(yrbrn < 1930 | yrbrn > 2000, NA, yrbrn),

  
    gen = case_when(
      yrbrn %in% 1900:1945 ~ "1",
      yrbrn %in% 1946:1964 ~ "2",
      yrbrn %in% 1965:1979 ~ "3",
      yrbrn %in% 1980:1996 ~ "4",
      TRUE ~ as.character(cohort)  # Keeping other values as character if they do not fit the ranges
    ),

    # Converting cohort to a factor with labels
    gen = factor(gen,
                 levels = c("1", "2", "3", "4"),
                 labels = c("Interwar", "Baby Boomers", "Gen X", "Millennials"))
  )
table(model_data$gen)
## 
##     Interwar Baby Boomers        Gen X  Millennials 
##         2978         3484         3498         2330
model1 <- lm(populist ~ lrscale, data = model_data)
model2 <- lm(populist ~ gndr, data = model_data)
model3 <- lm(populist ~ gen, data = model_data)
modelsummary(
  list(model1),
  fmt = 1,
  estimate  = c( "{estimate} ({std.error}){stars}"),
  statistic = NULL,
  coef_omit = "Intercept")
 (1)
lrscale 0.1 (0.0)***
Num.Obs. 9823
R2 0.021
R2 Adj. 0.021
AIC 88667.6
BIC 88689.2
Log.Lik. −44330.802
RMSE 22.07
models <- list(
   "Model 1" = lm(populist ~ lrscale, data = model_data),
   "Model 2" = lm(populist ~ gndr, data = model_data),
   "Model 3" = lm(populist ~ gen, data = model_data))
modelsummary(models, fmt = 1,
  estimate  = c("{estimate} ({std.error}){stars}",
                "{estimate} ({std.error}){stars}",
                "{estimate} ({std.error}){stars}"),
  statistic = NULL)
Model 1  Model 2  Model 3
(Intercept) 67.5 (0.3)*** 70.0 (0.3)*** 65.8 (0.5)***
lrscale 0.1 (0.0)***
gndrMale −1.0 (0.5)*
genBaby Boomers 3.5 (0.7)***
genGen X 5.6 (0.7)***
genMillennials 5.8 (0.7)***
Num.Obs. 9823 9823 9562
R2 0.021 0.000 0.009
R2 Adj. 0.021 0.000 0.009
AIC 88667.6 88873.2 86473.9
BIC 88689.2 88894.8 86509.7
Log.Lik. −44330.802 −44433.590 −43231.944
RMSE 22.07 22.30 22.25
modelplot(models, coef_omit = 'Interc')

modelsummary(models, fmt = 1,
  estimate  = c("{estimate} ({std.error}){stars}",
                "{estimate} ({std.error}){stars}",
                "{estimate} ({std.error}){stars}"),
  statistic = NULL,
  coef_rename = c("genBaby Boomers" = "Baby Boomers", "genGen X" = "Gen X", "genMillennials" = "Millennials", "gndrMale" = "Male", "educ.ba or more" = "left"),
  title = 'Table 2. Regression models for populist attitudes')
Table 2. Regression models for populist attitudes
Model 1  Model 2  Model 3
(Intercept) 67.5 (0.3)*** 70.0 (0.3)*** 65.8 (0.5)***
lrscale 0.1 (0.0)***
Male −1.0 (0.5)*
Baby Boomers 3.5 (0.7)***
Gen X 5.6 (0.7)***
Millennials 5.8 (0.7)***
Num.Obs. 9823 9823 9562
R2 0.021 0.000 0.009
R2 Adj. 0.021 0.000 0.009
AIC 88667.6 88873.2 86473.9
BIC 88689.2 88894.8 86509.7
Log.Lik. −44330.802 −44433.590 −43231.944
RMSE 22.07 22.30 22.25

Male, relative to female illustrates that on average, men have populist scale scores that are 1.0 points lower than feamles.

#End