Is this regression right? problems with panel dataset

Question

I'm running a panel regression with dependent variable GDP_capita and explanatory variables fulldemocracy (which is a dummy 0 or 1, 1 when polity index score is 9 or 10) and control variable for gdp_per_capita_initial_year.

I want to know whether democracies that have a high score (9 or 10 in polity index) have a larger growth for GDP_capita

I'm using the world bank index and polity data set. I merged these.

I'm looking between 1960 - 2010.

I try to run a panel regression. I'm not really into panel data. But I think I need to run an fixed effects regression.

plm.data and plm is from package plm

I want to make a panel data regression like the one in acemoglu et al. (2018) "Democracy does cause growth". I want to know whether democracies that have a high score have a larger growth for GDP_capita

This is a small version of the dataset :

> dput(df2)
structure(list(country = c("Afghanistan", "Afghanistan", "Afghanistan", 
"Afghanistan", "Afghanistan", "Afghanistan", "Afghanistan", "Afghanistan", 
"Afghanistan", "Albania", "Albania", "Albania", "Albania", "Albania", 
"Albania", "Albania", "Albania", "Albania", "Albania", "Albania", 
"Albania", "Albania", "Albania", "Albania", "Albania", "Albania", 
"Albania", "Albania", "Albania", "Albania", "Albania", "Albania", 
"Albania", "Albania", "Albania", "Albania", "Albania", "Albania", 
"Albania", "Albania", "Algeria", "Algeria", "Algeria", "Algeria", 
"Algeria", "Algeria", "Algeria", "Algeria", "Algeria", "Algeria", 
"Algeria", "Algeria", "Algeria", "Algeria", "Algeria", "Algeria", 
"Algeria", "Algeria", "Algeria", "Algeria", "Algeria", "Algeria", 
"Algeria", "Algeria", "Algeria", "Algeria", "Algeria", "Algeria", 
"Algeria", "Algeria", "Algeria", "Algeria", "Algeria", "Algeria", 
"Algeria", "Algeria", "Algeria", "Algeria", "Algeria", "Algeria", 
"Algeria", "Algeria", "Algeria", "Algeria", "Algeria", "Algeria", 
"Algeria", "Algeria", "Algeria", "Algeria", "Algeria", "Angola", 
"Angola", "Angola", "Angola", "Angola", "Angola", "Angola", "Angola", 
"Angola", "Angola", "Angola", "Angola", "Angola", "Angola", "Angola", 
"Angola", "Angola", "Angola", "Angola", "Angola", "Angola", "Angola", 
"Angola", "Angola", "Angola", "Angola", "Angola", "Angola", "Angola", 
"Angola", "Angola", "Argentina", "Argentina", "Argentina", "Argentina", 
"Argentina", "Argentina", "Argentina", "Argentina", "Argentina", 
"Argentina", "Argentina", "Argentina", "Argentina", "Argentina", 
"Argentina", "Argentina", "Argentina", "Argentina", "Argentina", 
"Argentina", "Argentina", "Argentina", "Argentina", "Argentina", 
"Argentina", "Argentina", "Argentina", "Argentina", "Argentina", 
"Argentina", "Argentina", "Argentina", "Argentina", "Argentina", 
"Argentina", "Argentina", "Argentina", "Argentina", "Argentina", 
"Argentina", "Argentina", "Argentina", "Argentina", "Argentina", 
"Argentina", "Argentina", "Argentina", "Argentina", "Argentina", 
"Argentina", "Argentina", "Armenia", "Armenia", "Armenia", "Armenia", 
"Armenia", "Armenia", "Armenia", "Armenia", "Armenia", "Armenia", 
"Armenia", "Armenia", "Armenia", "Armenia", "Armenia", "Armenia", 
"Armenia", "Armenia", "Armenia", "Armenia", "Armenia", "Australia", 
"Australia", "Australia", "Australia", "Australia", "Australia", 
"Australia", "Australia", "Australia", "Australia", "Australia", 
"Australia", "Australia", "Australia", "Australia", "Australia", 
"Australia", "Australia", "Australia", "Australia", "Australia", 
"Australia", "Australia", "Australia", "Australia", "Australia", 
"Australia", "Australia", "Australia", "Australia", "Australia", 
"Australia", "Australia", "Australia", "Australia", "Australia", 
"Australia", "Australia", "Australia", "Australia", "Australia", 
"Australia", "Australia", "Australia", "Australia", "Australia", 
"Australia", "Australia", "Australia", "Australia", "Australia", 
"Austria", "Austria", "Austria", "Austria", "Austria", "Austria", 
"Austria", "Austria", "Austria", "Austria", "Austria", "Austria", 
"Austria", "Austria", "Austria", "Austria", "Austria", "Austria", 
"Austria", "Austria", "Austria", "Austria", "Austria", "Austria", 
"Austria", "Austria", "Austria", "Austria", "Austria", "Austria", 
"Austria", "Austria", "Austria", "Austria", "Austria", "Austria", 
"Austria", "Austria", "Austria", "Austria", "Austria", "Austria", 
"Austria", "Austria", "Austria", "Austria", "Austria", "Austria", 
"Austria", "Austria", "Austria"), year = c(2002, 2003, 2004, 
2005, 2006, 2007, 2008, 2009, 2010, 1980, 1981, 1982, 1983, 1984, 
1985, 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 
1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 
2007, 2008, 2009, 2010, 1960, 1961, 1962, 1963, 1964, 1965, 1966, 
1967, 1968, 1969, 1970, 1971, 1972, 1973, 1974, 1975, 1976, 1977, 
1978, 1979, 1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988, 
1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 
2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 
1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988, 1989, 1990, 
1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 
2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 1960, 1961, 
1962, 1963, 1964, 1965, 1966, 1967, 1968, 1969, 1970, 1971, 1972, 
1973, 1974, 1975, 1976, 1977, 1978, 1979, 1980, 1981, 1982, 1983, 
1984, 1985, 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 
1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 
2006, 2007, 2008, 2009, 2010, 1990, 1991, 1992, 1993, 1994, 1995, 
1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 
2007, 2008, 2009, 2010, 1960, 1961, 1962, 1963, 1964, 1965, 1966, 
1967, 1968, 1969, 1970, 1971, 1972, 1973, 1974, 1975, 1976, 1977, 
1978, 1979, 1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988, 
1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 
2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 
1960, 1961, 1962, 1963, 1964, 1965, 1966, 1967, 1968, 1969, 1970, 
1971, 1972, 1973, 1974, 1975, 1976, 1977, 1978, 1979, 1980, 1981, 
1982, 1983, 1984, 1985, 1986, 1987, 1988, 1989, 1990, 1991, 1992, 
1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 
2004, 2005, 2006, 2007, 2008, 2009, 2010), GDP_capita = c(330.303552908057, 
343.080889714587, 333.216684486798, 357.234719908026, 365.284494951006, 
405.548979051796, 412.014286663305, 488.300250990155, 543.303041863931, 
1992.29193141135, 2064.98366201803, 2081.41762946956, 2060.25372979627, 
1992.11089530965, 1986.32191372468, 2058.12060889689, 2001.53265726801, 
1936.2322073095, 2070.28951506789, 1838.66748471688, 1331.80531341432, 
1243.60582446625, 1370.82607057959, 1493.78590178292, 1703.28184475531, 
1869.86587314624, 1676.12710708271, 1835.64668130129, 2085.42599716821, 
2244.62463172571, 2453.62441365203, 2572.72143217486, 2725.17138911963, 
2887.37034243453, 3062.67388299547, 3263.90171311883, 3485.32240934607, 
3775.58131429173, 3928.45039149695, 4094.3503344202, 2481.75865822178, 
2091.43473537687, 1638.75443167486, 2146.94057976366, 2214.88242258339, 
2290.65551809338, 2121.14452793897, 2256.52705127321, 2429.04937105024, 
2559.32258821122, 2708.47280988402, 2335.79152637326, 2895.79833918722, 
2925.11548989565, 3058.83456830849, 3124.42007771832, 3291.69790025388, 
3366.83815986028, 3571.5895226567, 3726.36511883879, 3643.69833817832, 
3638.92197468957, 3752.81654024129, 3833.82114831175, 3925.42390010012, 
3949.45517413828, 3850.10318077201, 3715.10483778964, 3577.26312225163, 
3636.07964185726, 3572.30015509623, 3443.65684595243, 3424.2093928921, 
3278.64646115576, 3182.54561872525, 3240.99021607688, 3315.23636358283, 
3297.99935564852, 3414.56223981336, 3474.27325785774, 3557.6386684294, 
3616.6833576974, 3770.82924514601, 3991.07992627792, 4108.19831659194, 
4290.53154268188, 4299.74842525472, 4377.49860061468, 4409.81203227677, 
4403.87344648228, 4480.79927130159, 3179.53912630862, 2934.3983409449, 
2831.97274724242, 2847.50235465173, 2912.665762525, 2909.52952662284, 
2890.01561405532, 2904.1301513259, 2976.63662969303, 2877.33890185971, 
2685.77913860722, 2623.71454945574, 2390.80826970707, 1759.35347818949, 
1726.31605022296, 1922.41659740388, 2113.75121066285, 2195.71932106392, 
2225.68482490823, 2201.52992280828, 2195.63104363877, 2213.68162733811, 
2433.80490448768, 2423.29450431622, 2597.45754126006, 2883.97881768389, 
3102.65158022739, 3409.50417848833, 3652.15426594294, 3549.57860280612, 
3587.88379824396, 5642.76513813328, 5853.17190550128, 5711.17933827409, 
5323.49430875299, 5772.64996675285, 6286.22934651492, 6151.92602594926, 
6255.18402161641, 6460.78745199298, 6980.89917797887, 7084.18147848151, 
7368.07758010525, 7368.50576960672, 7453.75355684331, 7740.85592849079, 
7617.94315128736, 7350.8285666498, 7743.58231487359, 7285.43955621042, 
7910.36662234598, 7908.02261816432, 7380.67498356137, 7210.34702077923, 
7403.72720995174, 7399.88911933586, 6904.64504404204, 7214.27070267463, 
7294.06425599089, 7104.18120080538, 6497.42554534223, 6245.70857662189, 
6721.27823910953, 7157.32831119985, 7644.23569200433, 7988.64461361092, 
7666.53000424516, 7994.24337081722, 8543.02853403286, 8772.06320960578, 
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7380.4670873289, 7962.41230916816, 8577.86499429459, 9174.50245831661, 
9901.51188115634, 10201.4759370923, 9502.24358504659, 10385.9644319555, 
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955.591035098613, 1042.58347163728, 1120.84988485751, 1171.05993764278, 
1266.41072717579, 1316.53041801902, 1403.03125693319, 1547.25096426637, 
1761.13404630652, 2018.36748633212, 2243.08895410475, 2571.54737414349, 
2933.58637167002, 3364.7057424114, 3627.79670232372, 3137.34609774988, 
3218.37270660563, 19378.3707946897, 19468.8178179858, 19245.6202628193, 
20053.3637890905, 21035.9183111766, 21861.9575878088, 21877.5774112563, 
22964.7001362559, 23712.9087182672, 24857.5440894284, 26120.6494734321, 
26263.4896717793, 26794.0220186405, 27077.1153049505, 27483.6869545714, 
27513.8685051962, 27944.2336293778, 28625.1942438694, 28547.9825448817, 
29383.0735686274, 29907.7863463789, 30419.5325316349, 30912.2222181387, 
29850.1943253301, 30866.2518242285, 32045.3160169279, 32797.0946430137, 
33126.7927129807, 34460.0365303649, 35191.1144375945, 35912.2092359937, 
35316.5370122119, 35034.5326599405, 36091.3889821234, 37133.6484007101, 
38095.1295333831, 39056.181021017, 40153.6122516886, 41555.9443532478, 
43168.2924609306, 44334.3929341041, 44585.1985160971, 45806.6944747073, 
46595.9009195353, 47926.7486611411, 48813.8877630783, 49443.225533311, 
51024.2411265745, 51841.2730313421, 51767.3778350805, 52022.1255961876, 
13031.0317692215, 13677.4644013835, 13953.9501954416, 14438.3568543653, 
15220.8199272257, 15648.5269132562, 16416.0056301174, 16783.8899182416, 
17443.7052192203, 18474.5402685695, 19573.8671463957, 20483.4535598112, 
21628.9664017571, 22561.3707979535, 23410.8905853717, 23387.7066979738, 
24501.7496582501, 25736.5515508775, 25703.1377080491, 27126.1785268963, 
27595.8351099017, 27485.8325124757, 28018.5412476123, 28898.2192222307, 
28914.8569636945, 29623.4345208073, 30285.9335797815, 30677.5443992108, 
31643.8093803121, 32726.0598533404, 33888.9960300827, 34707.0716937124, 
35045.844759146, 34941.1438607923, 35643.0281541159, 36537.9935189467, 
37346.00747133, 38084.702501734, 39405.4152181248, 40727.4844977123, 
42001.210774577, 42370.9302536426, 42859.3299380524, 43052.602598004, 
43956.5829032552, 44637.8560109729, 45951.7346365426, 47510.2937856663, 
48053.4823567215, 46123.4911031965, 46858.0432733717), Trade_perc = c(NA, 
NA, NA, NA, NA, NA, NA, 49.6634257108719, 52.5796000411513, 47.4940925041872, 
46.1004662837047, 44.8105616083383, 40.4106676033234, 38.1156830212927, 
35.9348239721958, 31.6373048780561, 32.159563916938, 36.89787073527, 
40.066086463479, 39.4369634031142, 36.0705200632829, 108.785472241159, 
80.518332770413, 53.1025847356112, 47.6105948729712, 44.895427261101, 
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66.4910464537142, 68.5250379172273, 67.0206085093238, 67.047228208342, 
70.8723282677903, 74.2670817296107, 83.2021007868277, 77.4517479127996, 
75.09481921411, 76.5433546212188, 106.186804301314, 113.7483279283, 
40.6125193571122, 61.510197197341, 54.5238212566159, 48.4370219064117, 
50.6397695218843, 45.066186093677, 47.3228889614156, 51.8595349042921, 
51.2254018061269, 46.1062966825765, 46.1764302847485, 57.0934265311372, 
74.2388192371426, 76.6545354056848, 70.1732568821597, 72.3268842306998, 
65.7045688895452, 64.0140492853508, 64.6769231605018, 65.4649936353318, 
59.9229312690034, 53.7441173561114, 53.1763836889134, 50.3261206307911, 
36.026710569926, 32.6845844686128, 38.111587277742, 47.1533197065802, 
48.3807136815584, 52.7175867077307, 49.1890842360411, 44.9228133698634, 
48.5844377877809, 55.1910052081435, 53.7051478767794, 52.2439115059386, 
45.0944505585079, 50.9295287505404, 62.860745986322, 58.7007948523846, 
61.1346953214823, 62.1258853095728, 65.7006716430047, 71.2787622322137, 
70.7298711992001, 71.9370462637257, 76.6844445249328, 71.3242375601926, 
69.8672404016145, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, 
NA, NA, NA, NA, NA, NA, NA, NA, NA, 152.547109454858, 150.335794690093, 
105.301742600149, 103.901226814948, 103.579924362095, 106.590962129525, 
94.6251593320477, 108.060067893978, 121.36470790564, 122.446142344145, 
104.123629959119, 15.2080960873797, 11.9898923109727, 14.0755256495637, 
15.7809062353749, 11.1274296795488, 10.3764574099485, 11.6426054171411, 
12.492660372918, 11.8881648852942, 12.7974266330598, 10.3374440809233, 
12.6151889155439, 14.0356431972715, 13.3221685115576, 13.1915798576321, 
11.8027242947756, 15.0968846246649, 16.9422865680472, 14.3237963724531, 
12.8406846410014, 11.5456724604615, 14.2929774789475, 15.6114860999886, 
14.9876701068591, 12.3463814292217, 18.009425070688, 14.4860327921395, 
15.448969882952, 15.743458608705, 19.6377977018838, 14.9908589999441, 
13.7530541588892, 14.730980586353, 16.2231514477839, 18.1343458669981, 
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21.3827449624898, 22.6224447777343, 21.8522554515453, 41.7527243585642, 
40.6447480311085, 40.692646108947, 40.5512709706238, 40.4334798719151, 
40.945170618571, 40.4026733790382, 34.0571269054879, 34.9710132635696, 
81.3357185450209, 100.865855188857, 101.076759405526, 107.973146280234, 
112.429364602262, 86.1148570667578, 79.2295601199241, 78.5477450545048, 
71.8424518815414, 70.5604791440404, 72.2333302273367, 69.8642663925336, 
73.984501843231, 80.0513676022426, 73.0706339919371, 70.1397385835334, 
61.0301379818566, 56.9750470853147, 54.5423279613666, 57.2742357441995, 
64.642975973633, 27.0496744634676, 27.4219284248917, 26.5679540592276, 
26.8329514684441, 28.6959800179085, 28.4813679347122, 28.0556924593396, 
26.7703190627072, 26.7768368361504, 25.2828227236593, 26.1919622262625, 
25.5916058937342, 24.7931840661811, 25.1693569461475, 26.3621582160871, 
29.01009022176, 26.9000648773338, 28.66956720861, 28.2150992670536, 
29.6651403610851, 32.3441672927996, 31.6487229036032, 30.3671689045293, 
29.2148849897175, 28.5821406143089, 32.5617520385408, 33.0890716261912, 
32.5850168703711, 32.6345364166847, 32.130350909175, 32.2202275569202, 
32.2555117521316, 33.1102641795285, 35.4665193170798, 36.5261284317788, 
37.8015516603413, 38.3323319414935, 38.0748112251054, 40.0704305582242, 
39.1346484106034, 41.0290111758291, 44.3652083634724, 41.5572758742756, 
40.2961446264483, 37.1207343685942, 39.2711826369216, 41.6042270907138, 
42.0514396834877, 42.8703326982714, 45.7979042094362, 40.6496717288741, 
NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, 54.86039174788, 54.3804711459358, 
54.2960192212936, 54.4568199360651, 59.5677317780406, 56.5991341566834, 
59.9162816321086, 60.2775956821567, 59.6679877608595, 63.3172191333532, 
66.8250060486283, 68.396550301208, 64.1171139234959, 62.4721849872476, 
66.5750060351522, 70.0831614762495, 64.014597212162, 62.8537227269269, 
66.562550344062, 70.5383587945509, 71.4883694819226, 70.0484058928522, 
67.6301674653756, 63.2650504915528, 65.9870933378821, 68.25660110272, 
70.0836711206827, 74.8676902155828, 76.9271493915785, 78.2601403439716, 
85.3604956179232, 87.5366647639352, 86.9481679996606, 86.3873824162825, 
90.7923456929297, 94.0338056833054, 98.0883112053436, 100.733254061926, 
102.073682731706, 87.0622309742796, 99.0197962369563), fulldemo = c(0, 
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, NA, NA, 
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1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 
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1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 
1, 1, 1), init_year = c(2002, 2002, 2002, 2002, 2002, 2002, 2002, 
2002, 2002, 1980, 1980, 1980, 1980, 1980, 1980, 1980, 1980, 1980, 
1980, 1980, 1980, 1980, 1980, 1980, 1980, 1980, 1980, 1980, 1980, 
1980, 1980, 1980, 1980, 1980, 1980, 1980, 1980, 1980, 1980, 1980, 
1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 
1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 
1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 
1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 
1960, 1960, 1960, 1960, 1960, 1960, 1960, 1980, 1980, 1980, 1980, 
1980, 1980, 1980, 1980, 1980, 1980, 1980, 1980, 1980, 1980, 1980, 
1980, 1980, 1980, 1980, 1980, 1980, 1980, 1980, 1980, 1980, 1980, 
1980, 1980, 1980, 1980, 1980, 1960, 1960, 1960, 1960, 1960, 1960, 
1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 
1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 
1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 
1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 
1960, 1990, 1990, 1990, 1990, 1990, 1990, 1990, 1990, 1990, 1990, 
1990, 1990, 1990, 1990, 1990, 1990, 1990, 1990, 1990, 1990, 1990, 
1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 
1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 
1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 
1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 
1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 
1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 
1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 
1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 
1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 1960, 
1960, 1960, 1960), gdp_capita_at_init_year = c(330.303552908057, 
330.303552908057, 330.303552908057, 330.303552908057, 330.303552908057, 
330.303552908057, 330.303552908057, 330.303552908057, 330.303552908057, 
1992.29193141135, 1992.29193141135, 1992.29193141135, 1992.29193141135, 
1992.29193141135, 1992.29193141135, 1992.29193141135, 1992.29193141135, 
1992.29193141135, 1992.29193141135, 1992.29193141135, 1992.29193141135, 
1992.29193141135, 1992.29193141135, 1992.29193141135, 1992.29193141135, 
1992.29193141135, 1992.29193141135, 1992.29193141135, 1992.29193141135, 
1992.29193141135, 1992.29193141135, 1992.29193141135, 1992.29193141135, 
1992.29193141135, 1992.29193141135, 1992.29193141135, 1992.29193141135, 
1992.29193141135, 1992.29193141135, 1992.29193141135, 2481.75865822178, 
2481.75865822178, 2481.75865822178, 2481.75865822178, 2481.75865822178, 
2481.75865822178, 2481.75865822178, 2481.75865822178, 2481.75865822178, 
2481.75865822178, 2481.75865822178, 2481.75865822178, 2481.75865822178, 
2481.75865822178, 2481.75865822178, 2481.75865822178, 2481.75865822178, 
2481.75865822178, 2481.75865822178, 2481.75865822178, 2481.75865822178, 
2481.75865822178, 2481.75865822178, 2481.75865822178, 2481.75865822178, 
2481.75865822178, 2481.75865822178, 2481.75865822178, 2481.75865822178, 
2481.75865822178, 2481.75865822178, 2481.75865822178, 2481.75865822178, 
2481.75865822178, 2481.75865822178, 2481.75865822178, 2481.75865822178, 
2481.75865822178, 2481.75865822178, 2481.75865822178, 2481.75865822178, 
2481.75865822178, 2481.75865822178, 2481.75865822178, 2481.75865822178, 
2481.75865822178, 2481.75865822178, 2481.75865822178, 2481.75865822178, 
2481.75865822178, 2481.75865822178, 3179.53912630862, 3179.53912630862, 
3179.53912630862, 3179.53912630862, 3179.53912630862, 3179.53912630862, 
3179.53912630862, 3179.53912630862, 3179.53912630862, 3179.53912630862, 
3179.53912630862, 3179.53912630862, 3179.53912630862, 3179.53912630862, 
3179.53912630862, 3179.53912630862, 3179.53912630862, 3179.53912630862, 
3179.53912630862, 3179.53912630862, 3179.53912630862, 3179.53912630862, 
3179.53912630862, 3179.53912630862, 3179.53912630862, 3179.53912630862, 
3179.53912630862, 3179.53912630862, 3179.53912630862, 3179.53912630862, 
3179.53912630862, 5642.76513813328, 5642.76513813328, 5642.76513813328, 
5642.76513813328, 5642.76513813328, 5642.76513813328, 5642.76513813328, 
5642.76513813328, 5642.76513813328, 5642.76513813328, 5642.76513813328, 
5642.76513813328, 5642.76513813328, 5642.76513813328, 5642.76513813328, 
5642.76513813328, 5642.76513813328, 5642.76513813328, 5642.76513813328, 
5642.76513813328, 5642.76513813328, 5642.76513813328, 5642.76513813328, 
5642.76513813328, 5642.76513813328, 5642.76513813328, 5642.76513813328, 
5642.76513813328, 5642.76513813328, 5642.76513813328, 5642.76513813328, 
5642.76513813328, 5642.76513813328, 5642.76513813328, 5642.76513813328, 
5642.76513813328, 5642.76513813328, 5642.76513813328, 5642.76513813328, 
5642.76513813328, 5642.76513813328, 5642.76513813328, 5642.76513813328, 
5642.76513813328, 5642.76513813328, 5642.76513813328, 5642.76513813328, 
5642.76513813328, 5642.76513813328, 5642.76513813328, 5642.76513813328, 
1795.28422592838, 1795.28422592838, 1795.28422592838, 1795.28422592838, 
1795.28422592838, 1795.28422592838, 1795.28422592838, 1795.28422592838, 
1795.28422592838, 1795.28422592838, 1795.28422592838, 1795.28422592838, 
1795.28422592838, 1795.28422592838, 1795.28422592838, 1795.28422592838, 
1795.28422592838, 1795.28422592838, 1795.28422592838, 1795.28422592838, 
1795.28422592838, 19378.3707946897, 19378.3707946897, 19378.3707946897, 
19378.3707946897, 19378.3707946897, 19378.3707946897, 19378.3707946897, 
19378.3707946897, 19378.3707946897, 19378.3707946897, 19378.3707946897, 
19378.3707946897, 19378.3707946897, 19378.3707946897, 19378.3707946897, 
19378.3707946897, 19378.3707946897, 19378.3707946897, 19378.3707946897, 
19378.3707946897, 19378.3707946897, 19378.3707946897, 19378.3707946897, 
19378.3707946897, 19378.3707946897, 19378.3707946897, 19378.3707946897, 
19378.3707946897, 19378.3707946897, 19378.3707946897, 19378.3707946897, 
19378.3707946897, 19378.3707946897, 19378.3707946897, 19378.3707946897, 
19378.3707946897, 19378.3707946897, 19378.3707946897, 19378.3707946897, 
19378.3707946897, 19378.3707946897, 19378.3707946897, 19378.3707946897, 
19378.3707946897, 19378.3707946897, 19378.3707946897, 19378.3707946897, 
19378.3707946897, 19378.3707946897, 19378.3707946897, 19378.3707946897, 
13031.0317692215, 13031.0317692215, 13031.0317692215, 13031.0317692215, 
13031.0317692215, 13031.0317692215, 13031.0317692215, 13031.0317692215, 
13031.0317692215, 13031.0317692215, 13031.0317692215, 13031.0317692215, 
13031.0317692215, 13031.0317692215, 13031.0317692215, 13031.0317692215, 
13031.0317692215, 13031.0317692215, 13031.0317692215, 13031.0317692215, 
13031.0317692215, 13031.0317692215, 13031.0317692215, 13031.0317692215, 
13031.0317692215, 13031.0317692215, 13031.0317692215, 13031.0317692215, 
13031.0317692215, 13031.0317692215, 13031.0317692215, 13031.0317692215, 
13031.0317692215, 13031.0317692215, 13031.0317692215, 13031.0317692215, 
13031.0317692215, 13031.0317692215, 13031.0317692215, 13031.0317692215, 
13031.0317692215, 13031.0317692215, 13031.0317692215, 13031.0317692215, 
13031.0317692215, 13031.0317692215, 13031.0317692215, 13031.0317692215, 
13031.0317692215, 13031.0317692215, 13031.0317692215)), row.names = c(NA, 
-296L), groups = structure(list(country = c("Afghanistan", "Albania", 
"Algeria", "Angola", "Argentina", "Armenia", "Australia", "Austria"
), .rows = structure(list(1:9, 10:40, 41:91, 92:122, 123:173, 
    174:194, 195:245, 246:296), ptype = integer(0), class = c("vctrs_list_of", 
"vctrs_vctr", "list"))), row.names = c(NA, 8L), class = c("tbl_df", 
"tbl", "data.frame"), .drop = TRUE), class = c("grouped_df", 
"tbl_df", "tbl", "data.frame"))

The dataset is unbalanced, since we don't have values for every single year for every country. I filtered on GDP_capita. So there are no missing values in GDP_capita.

Regression

Not all variables are taken into account here. What is the problem?

> fixed_4 <- plm(GDP_capita ~ 
+                  fulldemo + 
+                  gdp_capita_at_init_year + 
+                  Trade_perc + 
+                  fulldemo:gdp_capita_at_init_year +
+                  fulldemo:Trade_perc,
+                data = pdata_1, model = "within")
> summary(fixed_4)
Oneway (individual) effect Within Model

Call:
plm(formula = GDP_capita ~ fulldemo + gdp_capita_at_init_year + 
    Trade_perc + fulldemo:gdp_capita_at_init_year + fulldemo:Trade_perc, 
    data = pdata_1, model = "within")

Unbalanced Panel: n = 8, T = 2-51, N = 256

Residuals:
      Min.    1st Qu.     Median    3rd Qu.       Max. 
-10310.926   -950.521     48.425    739.441  12433.734 

Coefficients: (1 dropped because of singularities)
                      Estimate Std. Error  t-value Pr(>|t|)    
fulldemo            -54454.655   2965.356 -18.3636   <2e-16 ***
Trade_perc               8.960     18.846   0.4754   0.6349    
fulldemo:Trade_perc    732.561     36.888  19.8591   <2e-16 ***
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1

Total Sum of Squares:    7739100000
Residual Sum of Squares: 2.39e+09
R-Squared:      0.69118
Adj. R-Squared: 0.67858
F-statistic: 182.782 on 3 and 245 DF, p-value: < 2.22e-16

Hi bas_panel, welcome to StackOverflow. It is difficult to help you without having access to the data set you use. You can add the data by running `dput(mydata)` and pasting the output in your question. Also, what package does `plm.data` come from? Make sure your situation is reproducible. It seems like your data is grouped, that might cause an issue: try `ungroup()`. — Bas, Oct 29 '20 at 13:27
If the data set is too big, add part of it, for which your issue still persists, using for example `head()` or `filter()`: https://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example. An image does not help us run your example. — Bas, Oct 30 '20 at 07:38
You can select the first non-na observation of GDP_capita with `df1 %>% group_by(country) %>% filter(!is.na(GDP_capita)) %>% mutate(gdp_capita_at_init_year = first(GDP_capita))` — Bas, Oct 30 '20 at 10:09
Thank! But it also deletes the rows with missing values. For example at Afghanistan the rows 1960-2001 are deleted. Which causes my panel to be unbalenced. Won't that be an issue? — bas_panel, Oct 30 '20 at 10:16
I did what you told. However I'm running into some new problems. I fully updated it above! — bas_panel, Oct 30 '20 at 11:15
I don't know about the 'unbalanced' question, I'm sorry. I guess the new problems arise whenever `gdp_capita_at_init_year` is missing, or because of the fact that `gdp_capita_at_init_year` does not vary within a country. — Bas, Oct 30 '20 at 12:11

Is this regression right? problems with panel dataset

0 Answers0