model.qmd

---
title: "Model"
format: html
execute:
  echo: false
---

$$y_{i} = \beta_{0} + \beta_{1} modern + \beta_{2}great + \beta_{3}nuclear$$

We are using a linear model with error terms on the dependent variable of whether armed hostility occurs in a given conflict. Our model predicts negative relationships between nuclear possession, great power status, and modernity with chance of severe escalation.

```{r}
#| label: setup
#| message: false
library(tidyverse)
library(dplyr)
library(primer.data)
library(brms)
library(tidybayes)
library(gtsummary)
```

```{r}
#| label: data

DYMID<-read.csv("dyadic_mid_4.02.csv")


DYMID$year <- as.integer(DYMID$year)
DYMID$strtyr <- as.integer(DYMID$strtyr)
DYMID_N <- DYMID %>% mutate(modern=case_when((strtyr<1945)~0,(strtyr>=1945)~1))
DYMID_N <- DYMID_N %>% mutate(nucleara = case_when(
  (strtyr<1945) ~ 0,
  (
    ((namea=="USA") & (strtyr >= 1945)) |
    ((namea=="RUS") & (strtyr >= 1949)) |
    ((namea=="UKG") & (strtyr >= 1952)) |
    ((namea=="FRN") & (strtyr >= 1960)) |
    ((namea=="CHN") & (strtyr >= 1964)) |
    ((namea=="ISR") & (strtyr >= 1966)) |
    ((namea=="IND") & (strtyr >= 1974)) |
    ((namea=="PAK") & (strtyr >= 1998)) |
    ((namea=="PRK") & (strtyr >= 2006)) 
    ) ~ 1,
  stateb > 450 ~ 0),
  nuclearb = case_when(
  (strtyr<1945) ~ 0,
  (
    ((nameb=="USA") & (strtyr >= 1945)) |
    ((nameb=="RUS") & (strtyr >= 1949)) |
    ((nameb=="UKG") & (strtyr >= 1952)) |
    ((nameb=="FRN") & (strtyr >= 1960)) |
    ((nameb=="CHN") & (strtyr >= 1964)) |
    ((nameb=="ISR") & (strtyr >= 1966)) |
    ((nameb=="IND") & (strtyr >= 1974)) |
    ((nameb=="PAK") & (strtyr >= 1998)) |
    ((nameb=="PRK") & (strtyr >= 2006))
    ) ~ 1,
  strtyr  >= 1945 ~ 0) 
  ) %>%
  select(nucleara,nuclearb,strtyr,namea,nameb,everything()) %>%
  arrange(desc(nucleara))

DYMID_N <- DYMID_N %>% mutate(greata = case_when(
    ((namea=="AUH") & (strtyr <= 1918)) |
    ((namea=="CHN") & (strtyr >= 1896)) |
    ((namea=="UKG") & (strtyr >= 1952)) |
    (namea=="FRN") |
    (namea=="GMY") |
    (namea=="ITA") |
    (namea=="RUS") |
    (namea=="UKG") |
    (namea=="USA") ~ TRUE,
    TRUE ~ FALSE
  ),
  greatb = case_when(
    ((nameb=="AUH") & (strtyr <= 1918)) |
    ((nameb=="CHN") & (strtyr >= 1896)) |
    ((nameb=="UKG") & (strtyr >= 1952)) |
    (nameb=="FRN") |
    (nameb=="GMY") |
    (nameb=="ITA") |
    (nameb=="RUS") |
    (nameb=="UKG") |
    (nameb=="USA") ~ TRUE,
    TRUE ~ FALSE
  ),
)

DYMID_N <- DYMID_N |> drop_na() %>% mutate(nuclear=nucleara+nuclearb) %>%
  select(nuclear,everything()) %>%
  arrange(desc(nuclear))

DYMID_N <- DYMID_N |> drop_na() %>% mutate(great=greata+greatb) %>%
  select(great,everything()) %>%
  arrange(desc(great))


DYMID_N <- DYMID_N |> mutate(modern=case_when(
  (strtyr<=1945)~FALSE,
  (strtyr>1945)~TRUE,
  TRUE ~ NA))

DYMID_N <- DYMID_N |>
mutate(escalated=case_when(
  (hihost<=3)~FALSE,
  (hihost>3)~TRUE,
  TRUE ~ NA))

DYMID_N <- (DYMID_N |> drop_na())
DYMID_N <- DYMID_N |> select(great, nuclear,strtyr,modern,outcome,hihost,escalated,settlmnt,fatlev,highact,cumdurat)

DYMID_N <- DYMID_N |> mutate(great=as.factor(great))
DYMID_N <- DYMID_N |> mutate(nuclear=as.factor(nuclear))

set.seed(9)

nuclear_data <- DYMID_N  |> 
  drop_na() 

```


```{r}
#| label: model
#| cache: true

fit_nuclear<-brm(formula = escalated ~ modern+great+nuclear, data = nuclear_data, family = bernoulli(), refresh = 0, silent = 2, seed = 19)
```

```{r}
#| label: plot
#| message: false

fit_nuclear |>
tbl_regression()
```